644 Computer Service and Repair
Symptom 5:
The PC powers on, but there is no drive activity.
Items to check:
Check the system CMOS settings. Make sure the drive is identified.
The drive should be identified in the setup program as far as the number of
cylinders, heads, and sectors. In addition, while the PC is booting, the hard drive
manufacturer followed by the hard drive model number will often flash on the
screen when the BIOS finds it. If the drive is not detected during the boot, the
screen will flash something similar to “No Hard Disk Drive.”
You should also check the connections between the power supply and
the hard drive and the motherboard and the hard drive. They should be tight.
If all that checks out, boot the system with a boot disk. From the command
prompt, see if you can access the hard drive. If you can access the hard drive,
change your default directory to C:\Windows. When in the Windows directory,
type
win
to see if you can start Windows.
Symptom 6:
There is normal boot activity, lights and sounds, but no video.
Items to check:
Check if the monitor is plugged into the computer and that the monitor
has power. Swap the monitor out for a monitor that is known to be good. If the
system still fails to generate a display, you probably have a bad video adapter
card. Try reseating the video adapter card. If the system will still not display,
change the video adapter card.
Symptom 7:
The system crashes or reboots for no apparent reason.
Items to check:
Check the power supply and cables. Make sure they are all tight. Check for
excessive heat on the CPU and memory chips. Make sure all DIMMs are seated
properly. Try reseating the CPU.
If all of that hardware checks out, you likely have a defective motherboard
or there is a problem with the hard drive. Swapping hard drives with one you
know is working should show you where the problem lies. If the hard drive is
causing the problem, check for a virus or a corrupt operating system. Always
think about the last thing that occurred on the PC before the problem developed.
For example, did you or your client recently install a new software program? The
following section looks at hard drive failures in more detail.
Hard Drive Failures
Hard drives fail more often than would be thought. Any component that is
an electronic and a mechanical combination will fail after a period of time. In
addition, hard drives can fail because of software issues. A corrupt MBR can
cause hard drives to be unresponsive. It is important for you to determine more
than just if a hard drive is bad. You must also determine why it is bad.
A bad hard drive or a corrupt MBR will generate a screen message such as
one of the following: