|I really don't think fixing the file associations will work at this point.|
'i downloaded a trial of mcafee which cleared out all viruses but now my computer seems to be going funny.'
What AV are you using? If not McAfee, I would suggest uninstalling McAfee using the uninstaller from their website....you CANNOT use 2 AV's at the same time.
Sounds to me like you are still infested with malware.
You can run:
2- Trojan Remover
3- Hitman Pro.
They will all remove whatever infections they find.
Some HELP in posting on Computing.net plus free progs and instructions Cheers