Go to recovery console via the Winxp CD, then type in
chkdsk /f and then
sfc /scannow. Failing that, it may be time to do some good ol' troubleshooting.
1. Print this if you need it. Turn off the PC, unplug it from the wall socket, touch the case to de-static yourself.
2. open up the pc, look for
-damage: strange/burnt smells, popped capacitors, unnatural marks on the motherboards etc
3. Pull out everything except for your CPU, Motherboard, PSU, HDD, 1 stick of ram, and then use integrated audio/video if possible. try booting now, and/or try recovery console now.
4. pull out the HDD, and install on another pc available in slave mode, or a IDE>USB HDD case/converter, and see if it can read the HDD. If it can, backup any data you hold precious now. If it can't, download a disk diagnostic utillity from the relavant manufacturer for your hdd:
Seagate,
Maxtor,
Western Digital, and run the test.
Mkoll, i beleive you have a thread already "Hard Drive Problems"(?) and is about having trouble installing windows right? Do the above, and also check your Winxp CD is clean, scratchless, or not dodgy. Also, when you do put the cd in are you able to get to the windows installer at all? If you can, when its scanning for your hardware, in which point since you have a SATA HDD you'll need to press F6 to load the third party drivers for the HDD, usualy found in your motherboard's CD. Post the in your other thread, since i've subscribed to it and will help you there, so not to confuse myself fixing 2 people in one go..