Need to rid myself of some nasty Malware

[Joe 90]

oh noes - gots some nasty adware/spyware.

It would appear my brother/mother have cocked up this laptop whilst i've been at uni.
I got back last week and it had some 'Win AntiVirus 2007' installed so i'm guessing things started with an IE popup saying 'youre computer is not protected, install this now!!'

so i've ran spybot/ccleaner/avast scans which all claim to do their job but still this thing seems to have a couple of startup scripts which shouldn't rund, and i also get two rundll32 errors because i've removed two files that this nasty stuff obviously wanted.

now, one thing we've got is definately this Vundo Trojan which spybot says its removed a few times, but it keeps coming back alongside some others.
Anyway, if these apps can't get rid, can anyone advise what i do?
i tried to run through regedit with symantec's advise from that site, but some of the reg keys didn't exist, but those that did, got removed. not sure what else to do really.

*edit*
don't know if its related, but Windows update just failed, twice to install office sp1 and a security patch. And facebook keeps failing to upload any photos (even just a sinlge 30kb image!)