I have been using InoculatePE for almost a year now. HIGHLY RECOMMENDED!!! A friend of mine had 5 active viruses on her system, McAfee didn't even catch them. I ran InoculateIT on her system and they were detected, and cleaned in a few short moments. Also, uses FAR LESS resources than McAfee did.
Also, just use the uninstall in add/remove programs to get rid of McAfee. Then use regclean of equivelant to get rid of the left over keys. Should work.... should.