Desktop

I have had luck booting from floppy disk to the command prompt and running the command
FDISK /MBR

This will fix a corrupted boot record on the hard drive and will usually let it boot up.
On occasion you will also need to copy the command.com and/or other boot files.

I don't recommend running the SYS command unless you have another PC to get a copy of MSDOS.SYS, this file tells WINDOWS how to start up and if you run SYS your system will
boot to Dos Prompt every time.

Shawn

Have you moved the computer around or installed any new hardware? If so, check the cable on the HDD and the motherboard. Also check the CMOS battery. If it is low, it will lose the some of the BIOS information, mainly the hard drive parameters.
Hope this helps.

More than likely your ide cable has come loose. Just press it in firmly and this should resolve this problem. This happened me last week just moving a computer from one room to another.

Answer number one hit the nail right on the head. What was suggested should be the first steps to take. The other thing to keep in mind is the placement of the CPU. Ensure it is located in a position that the internal fan can properly **** out the hot air or you may find more problems than just a hard drive. Remember, all information for the hard drive is located in block 0. If this block becomes corrupt, it will need to be replaced.

In addition to the IDE cable comng loose as suggested by someone else earlier, another frequent failure with respect to cables are the cable connectors. The connectors use what is called "insulation displacement" technology where the sharp pins inthe connector pierce the insulation to make contact with the connector inside. After a while, the insulation tends to push away from the pins and you can get an intermittent connection.

Take a pair of pliers and gently squeeze along the lengthof the connector to reestablisha good connection.