Win xp won't start

Hi guys,
I have been running winxp since it was first released with no problems, and had all the current updates.
Recently it started crashing occasionally, and coming up with the message: windows has recovered from a serious error....I figured it was time for a reformat, and clean out the system. This worked fine and ran with no problems for 2-3 weeks. Yesterday I got the same error message, so I tried to run a scandisk on reboot - but I couldn't reboot. I ran chkdsk and found errors, but this made no difference to the reboot. Eventually I had to reinstall windows over the top of the old one, but the boot is still locking up at the same stage (under safe mode, it is at driver c:\windows\system32\drivers\mup.sys).
Occasionally the boot works if I click the F8 option "Use the last known configuration that worked" - but only occasionally. I expect that my harddrive is on the way out - can anyone confirm or debunk this?

I read in another post, that perhaps you should try to flash your BIOS, that seemed to sort the mup.sys problem.
Go to the Storage forum and get the HD-manufacturer's util to test your HD.
http://www.techspot.com/vb/topic7602.html

Thanks for your help - seems my hard drive is on its last legs.