Error Loading Operating System

[OpSys Error]

Useing Win XP. The PC boots up, goes thourgh system and memory checks fine but then gives me the message: Error Loading Operating System. I tried booting with the XP disk to reinstal Windows if necissary. The comp seems to boot form the CD ok but only gets as far as checking system fo r hardware. At that point the screen goes blank, the CD doesn't spin, the CPU light doesn't flash and the only noise is the fans. There was a similer post I haven't been able to find again where the user solved it with a low level format useing some Maxtor softwhare I believe. I want to keep all my data so reformating must be a last resort.
I defragged the HD the previous day and the system was fine after that. I used it all morning then shut it down to go to work. When I booted it up later in the evening I got the error. The HD being a Western Digital IDE 200g is too large for XP so when I put it all together I partitioned it to a 100 and an 80 but it had been running fine like that for 6 months. The defrag may have triggered it but I don't see how.

1.7 AMD XP
DFI AD 77 Infinity MB
1G DDR RAM
200g Western Digital IDE 1100 RPM HD
64M ATI Raydeon



Any assistance would be much appriciated.

[Cricket]

Try another IDE cable.

Go to the hard drive manufacturer's web site and get the hard drive diagnostic utilities and test the drive.

Remove 1 stick of RAM at a time and see if the system runs properly. If the system runs well with 1 stick but not the other, you got a bad stick.

Cricket