Upgrading and Repairing PCs Tip #25: Top 12 PC Troubleshooting Problems and Solutions
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These are some of the most frequently asked troubleshooting questions I receive, along with the solutions that typically address them.
When I power the system on, I see the power LED light and hear the fans spin, but nothing else ever happens.
The fact that the LEDs illuminate and fans spin indicates that the power supply is partially working, but that does not exclude it from being defective. This is a classic “dead” system, which can be caused by almost any defective hardware component. In my experiences I’ve had more problems with power supplies than most other components, so I recommend immediately using a multimeter to measure the outputs at the power supply connectors and ensure they are within the proper 5% tolerances of their rated voltages. Even if the voltage measurements check out, you should swap in a high-quality, high-power, known-good spare supply and retest. If that doesn’t solve the problem, you should revert to the bootstrap approach I mentioned earlier, which is to strip the system down to just the chassis/power supply, motherboard, CPU (with heatsink), one bank of RAM (one DIMM), and a video card and display. If the motherboard now starts, begin adding the components you removed one at a time, retesting after each change. If the symptoms remain, use a POST card (if you have one) to see whether the board is partially functional and where it stops. Also, try replacing the video card, RAM, CPU, and then finally the motherboard, and verify the CPU and (especially) the heatsink installation.
The system beeps when I turn it on, but there is nothing on the screen.
The beep indicates a failure detected by the ROM POST routines. Look up the beep code in the table corresponding to the ROM version in your motherboard. This can typically be found in the motherboard manual; however, you can also find the beep codes for the most popular AMI, Award, and PhoenixBIOS earlier in this chapter.
I see a STOP or STOP ERROR in Windows.
Many things, including corrupted files, viruses, incorrectly configured hardware, and failing hardware, can cause Windows STOP errors. See the section “Operating System Diagnostics” earlier in this chapter for more information on troubleshooting Windows error messages. One of the most valuable resources for handling any error message displayed by Windows is the Microsoft Knowledgebase (MSKB), an online compendium of articles covering all Microsoft products. You can visit the MSKB at http://support.microsoft.com, and from there you can use the search tool to retrieve information specific to your problem.
I see Fatal Exception errors in Windows 95/98/Me.
This is the equivalent of the STOP error in Windows NT or later. As indicated in the previous answer, this can be caused by both hardware and software problems, and the best place to check for specific solutions is in the Microsoft Knowledgebase (MSKB) at http://support.microsoft.com.
The system won’t shut down in Windows.
This problem is usually caused by driver problems. (Try installing the latest chipset and power management drivers for your motherboard.) However, it can also be caused by bugs in motherboard ROM (try upgrading your motherboard ROM to the latest version), bugs in the various Windows versions (run Windows Update from Control Panel and install the latest fixes, patches, and service packs), or in some cases configuration or hardware problems.
The power button won’t turn off the system.
Desktop PCs built since 1996 mostly use the ATX form factor power supplies, which incorporate a design such that the Power Switch is connected to the motherboard and not the power supply directly. This enables the motherboard and operating system to control system shutdown, preventing an unexpected loss of power that can cause data loss or file system corruption. However, if the system experiences a problem and becomes frozen or locked up in some way, the motherboard might not respond to the power button, meaning it will not send a shutdown signal to the power supply. It might seem that you will have to pull the plug to power off the system, but fortunately a forced shutdown override is provided. Merely press and hold down the system power button (usually on the front of the chassis) for a minimum of 4 seconds, and the system should power off. The only drawback is that, because this type of shutdown is forced and under the control of the motherboard or operating system, unsaved data can be lost and some file system corruption can result. You should therefore run ScanDisk (Windows 2000 and earlier) or Chkdsk /F (Windows XP and later) from a command prompt to check for and correct any file-system issues after a forced shutdown.
I can’t connect to the Internet.
First, find out if any other computers or devices on your network can connect to the Internet. If not, check the broadband modem’s signal lights to see if you have a connection. If you do not have a connection, contact the ISP for help.
If you have a connection, unplug the router from AC power for about a minute and then plug it back in again. Computers with a wired connection will automatically reconnect. Wireless devices might reconnect automatically, or you might need to reconnect manually.
If only one device can’t connect, check the following. On a wired connection, make sure the Ethernet cable is plugged into working ports on the router or switch and the computer or device. Most Ethernet ports on computers have signal lights that flash to indicate a connection. If the signal lights are not flashing and the computer or device is turned on, the cable might be damaged. Test the cable and replace it if defective. If the connection is wireless, make sure the wireless radio is turned on. On many laptops, you can press a function-key or key combination or press a button on one side of the laptop to turn the wireless radio off and on. If the device uses a USB adapter, make sure it’s plugged in.
If you still can’t connect, run Windows troubleshooters for network and Internet connectivity. You can run these from Help and Support or from the Network and Sharing Center.
The keyboard doesn’t work.
The two primary ways to connect a keyboard to a PC are via the standard keyboard port (usually called a PS/2 port) and via USB. One problem is that some older systems that have USB ports cannot use a USB keyboard because USB support is provided by the operating system—for instance, if the motherboard has a USB port but does not include what is called USB Legacy Support in the BIOS. This support is specifically for USB keyboards (and mice) and was not common in systems until 1998 or later. Many systems that had such support in the BIOS still had problems with the implementation; in other words, they had bugs in the code that prevented the USB keyboard from working properly. If you are having problems with a USB keyboard, check to ensure that USB Legacy Support is enabled in the BIOS. If you are still having problems, make sure you have installed the latest BIOS and chipset drivers for your motherboard and any Windows updates from Microsoft. Some older systems never could properly use a USB keyboard, in which case you should change to a PS/2 keyboard instead. Some keyboards feature both USB and PS/2 interfaces, which offer the flexibility to connect to almost any system.
If the keyboard is having problems, the quickest way to verify whether it is the keyboard or the motherboard is to simply replace the keyboard with a known-good spare. In other words, borrow a working keyboard from another system and try it. If it still doesn’t work, the interface on the motherboard is most likely defective, which unfortunately means that the entire board must be replaced. If the spare keyboard works, then obviously the original keyboard was the problem.
I can’t hear sound from the speakers.
This can often be as simple as the speakers being unplugged, plugged into the wrong jacks, or powered off, so don’t overlook the obvious and check to be sure! Also check the volume controls in Windows or your application to see that they are turned up and not muted. When you are sure the volume is turned up, the speakers have power and are plugged in, and the speaker configuration is correctly identified in Windows (some audio hardware uses a proprietary mixer control for this job), you need to verify whether the problem is with the speakers or the sound card. To do this most efficiently, you merely connect different known-good speakers and see whether they work. If they don’t, clearly the issue is in the sound card—possibly the configuration of the card is incorrect or the card itself is defective. The first thing to try is clearing the ESCD in the BIOS Setup. This essentially forces the plug-and-play routines to reconfigure the system, which can resolve any conflicts. If this doesn’t help, try removing and reinstalling the sound card drivers. Finally, if that doesn’t help, physically remove and replace the card from the system. You might try replacing it first in the same slot and then in a different slot because timing issues can sometimes exist from one slot to the next. If that doesn’t work, you must try replacing the card. If the sound “card” really isn’t a card but is integrated into the motherboard, first try the ESCD reset and driver reinstallation. Then, if that doesn’t work, you have to try disabling the integrated sound and perhaps installing a replacement card or replacement motherboard.
If your problem is only with playing audio CDs, check for a cable between the sound card and the drive. If there is no cable, check the properties for the drive in the Device Manager in Windows to see whether the Digital CD Audio option is checked (enabled). If it’s not, enable it. If your system will not allow digital CD audio to be enabled, it is not supported and you must install an analog cable connected between the sound card and the drive.
The monitor appears completely garbled or unreadable.
A completely garbled screen is most often due to improper, incorrect, or unsupported settings for the refresh rate, resolution, or color depth. Using incorrect drivers can also cause this. To check the configuration of the card, the first step is to power on the system and verify whether you can see the POST or the system splash screen and enter the BIOS Setup. If the screen looks fine during the POST but goes crazy after Windows starts to load, the problem is almost certainly due to an incorrect setting or configuration of the card. To resolve this, open the special boot menu and select Windows Safe mode (hold down the F8 function key as Windows starts to load to display this menu).
This bypasses the current video driver and settings and places the system in the default VGA mode supported by the BIOS on the video card. When the Windows desktop appears, you can right-click the desktop, select Properties, and then either reconfigure the video settings or change drivers as necessary.
If the problem occurs from the moment you turn on the system, a hardware problem may exist with the video card, cable, or monitor. First, replace the monitor with another one; if the cable is detachable, replace that, too. If replacing the monitor and cable does not solve the problem, the video card is probably defective. Either replace the card or, if it is a PCI-based card, move it to a different slot. If the video is integrated into the motherboard, you must add a separate card instead or replace the motherboard.
The image on the display is distorted (bent), shaking, or wavering.
This can often be caused by problems with the power line, such as an electric motor, an air conditioner, a refrigerator, a microwave oven, and so on, causing interference. Try replacing the power cord, plugging the monitor or the system into a different outlet, or moving it to a different location entirely. I’ve also seen this problem caused by local radio transmitters such as a nearby radio or television station or two-way radios being operated in the vicinity of the system. If an LED or LCD display is plugged into a VGA port, use the OSD to auto-tune the display. Finally, if the problems persist, replace the monitor cable, try a different (known-good) monitor, and finally replace the video card.
I purchased a video card, and it won’t fit in the slot.
Most video cards are designed to conform to the PCI Express x16 specification. It is all but impossible to install a PCI Express x16 card into a non–PCI Express x16 slot, but if your system uses an older AGP 4X or 8X slot, problems can arise with these cards when they’re used with older AGP systems.
Both AGP 4X and AGP 8X are designed to run on only 1.5V.
Most older motherboards with AGP 2X slots are designed to accept only 3.3V cards. If you were to plug a 1.5V card into a 3.3V slot, both the card and motherboard could be damaged. Special keys have therefore been incorporated into the AGP specification to prevent such disasters. Typically, the slots and cards are keyed such that 1.5V cards fit only in 1.5V sockets and 3.3V cards fit only in 3.3V sockets. Additionally, universal sockets are available that accept either 1.5V or 3.3V cards. The keying for the AGP cards and connectors is dictated by the AGP standard, as shown in Figure 19.10.
FIGURE 19.10 AGP 4X/8X (1.5V) card and how it relates to 3.3V, universal, and 1.5V AGP slots.
As you can see from Figure 19.10, AGP 4X or 8X (1.5V) cards fit only in 1.5V or universal (3.3V or 1.5V) slots. Due to the design of the connector and card keys, a 1.5V card cannot be inserted into a 3.3V slot. So, if your new AGP card won’t fit in the AGP slot in your existing motherboard, consider that a good thing because, if you were able to plug it in, you would have fried both the card and the board! In a case such as this, return the AGP 4X/8X card and check surplus outlets or eBay for a compatible card.