Can't install .Net after removing trojan

Hi all, after struggling to remove a virtumonde from my laptop (which I think is now gone) I have been getting various strange error messages:

Userinit.exe - application error (which I think was to do with .net not working so I managed to uninstall it...I think!) and that error has not popped up again but am unable to install any other .net framework.

I have now been getting the following messages on startup:

Fatal Execution Engine Error (0x7927f26e) and
acstartup.exe (autocad startup problem which I havent had before) and
hpqthb08.exe (hpdigital imaging program startup problem)

I am running Windows XP professional and am not that computer savy!

If anyone has any suggestions they would be greatly appreciated...I have been trying to fix this all weekend. Thanks.

 

If you're sure you got rid of the malware, do a system scan or even a repair install. Either will require the windows setup disk.

http://www.updatexp.com/scannow-sfc.html

 

Thanks akhilles, I dont have the disk but have managed to get the info from the microsoft site...it all seems to be working ok now!