laptop hd was coming up with ntldr missing so took out hd and rigged it up via usb to 2nd pc and managed to save a couple of files but when i acess it now it says it is corrupt or inaccesable, when i click on properties the file system is RAW not NTFS
Sounds as though this hdd has been corrupt in some way or wiped. Your options are limited unless you pay a third party recovery company to retrieve your lost data, the other way is to re-format the drive and reinstall your os etc. What laptop do you have, and does it have a recovery programme built into the BIOS? This is usually accesed by pressing alt+F10 on bootup or similar, your manual should explain this, but if you have no backups re-formmating and re-install from a windows cd is your best bet. If this fails then the drive itself may have expired.
did you read the WHOLE page? maybe it would be a good idea to print the page and study it. It tells you how to make a CD
Also if I have understood your post ""can format and install on a different pc but when i put the hd bak in the faulty pc it comes up ntldr is missing"" I do not think you can swap a hard drive to another pc and expect XP to work (Because a Hardware Hash is generated during installation that 'ties' the installation of XP to that pc) but I may be wrong...
Lotvic is right, you cannot put a hard drive with with a windows installation from another pc into your other machine. Still think that this could be a virus but another thing to check is your BIOS settings (usually delete or f2 on bootup) check to make sure that boot sector virus protection is DISABLED and try again.