Bizarre explorer.exe problem

For the last day or so I've not been able to use my (admin) account on WinXP because a soon as I to load my account it gets to loading the taskbar etc and effectively freezes, I ctrl-alt-del and see that explorer.exe is taking up 100% CPU processes. The bizzare thing is it's only my account which is affected, which wouldn't be a huge problem other than I cannot now access my (irreplaceable, back up regularly, i know ) files. I am currently logged on as guest which is working like a charm. I cannot for the life of me think what may have caused this problem, other than my brother apparently opened an email attatchment yesterday which reset the computer, but apparently did nothing else. Does anyone have any ideas either to simply fix the problem outright or to rescue all my documents (settings if possible).

I'm running:
Athlon XP2000+
512mb PC333 DDR RAM
Nvidia GeForce Ti4200
SoundBlaster Live! 4:1
GigaByte m0b0
Windows XP Home (w/o the CD, apparently. However I can get it from the company that built this PC if necessary)

So far I have run adaware and Norton AV to no avail, and it is possible to close explorer.exe down, but obviously that restricts my options of what to do after!
Any more info required?
Please help, this is an unbelievably irritating problem.
Thanks in advance.

Fricking idiot question: how do I put it in safe mode, I forgot

DeaJae said:

When you close Explorer.exe in NT you can call up the Taskmanager in the usaul NT fashion, and run Explorer.exe, if that works better then something on boot is affecting it.
Probaly a virus, or corruption. Try Safe Mode as well as viruses in critical system files will clse down/hide from AV's in normal mode.

Click to expand...

I tried both of these and neither worked :/
When explorer.exe was restarted it just went straight back to 100% CPU, and full system virus scans found nothing, safe mode or no.
Does anyone else have any ideas? May replacing explorer.exe with a clean copy from the CD work? Thanks for the help so far.