It isn't a virus, simply a very persistent piece of software.
Try using System restore to go to before you installed it but remember to update McAfee immediately afterwards. If that doesn't work then try this....
Try running the free versions of these two anti-malware applications, update them first and use them in the order I post them.
Let them remove everything they find and reboot if asked to.
If you suspect you're infected and have trouble finding what is causing the infection, I'd suggest giving this handy tool a try.
"McAfee GetSusp is intended for users who suspect undetected malware on their system. By using a combination of clever heuristics and querying McAfee's online database of known clean files to gather suspicious files, GetSusp eliminates the user's need for deep technical knowledge of computer systems to isolate undetected malware. McAfee GetSusp is recommended as a tool of first choice when analyzing a suspect machine."
Get it from here:
Once GetSusp identifies and collects the suspect files, post the logs here and we community members can help.
Technical Product Manager, McAfee Labs