First hint you may have to restore xp in original format by formatting the disk once again
Only if not under manufacturer warranty, coz manufacturer like dell cancel your policy if you open the box so let's try this trick open the case unplugged first!!! make sure not touching other components verify cables on hard disk remove jumper coz having one drive there is no issue with master or slave try to run the pc without the hard disk...switch off again and plug it back without jumper, verify cabling on motherboard and HDD and start again... see what is happening... do not touch component to avoid EDC -electrostatic discharge which may damage your system
if nothing happening reboot with the HDD in, go in MS mode and try to reload system from your backup disk to have the A: at the invite then type c: +enter (or the letter you used before to access this drive)- just to check if you can read it in MS mode- then type at c:>dir/p, press enter and see if you can read repertory tree and folders. If you have important data, try to backup your perso data onto a floppies - tough process
If not, my advice buy a another HDD from maplink bigger size 200GB ~£80+vat i think make sure to mention what type of connection from the current HDD: IDE, SCSI or SATA... and put back the old one as a slave new as master (jumper back please) make sure your pc does not reboot on this old drive (bios selection, remove any allocation to old disk, ideally reboot from cd drive to config new HDD in the bios, make sure other booting selection default to c drive) Once you have this new HDD in place you could go back reading and saving your old data back to the new HDD and format the old one in NTFS format!
I run four HDD with two you should be ok with your current alimentation/power supply wise to consider having more than 250w check on the back of the PC
Your current HDD could be faulty...
I can guide you more if needed...