Computer has a Trojan I cannot get rid of. HOW do I get rid of this thing?

McAfee is rubbish at this. If you can not get to good internet site, re-start in safe mode and Google malwarebytes. Down load and save it to the desktop. Re-start in normal and install it. Then check for updates and finally run a quick scan. It will probably request a restart to finish repairs. Then uninstall McAfee and install a decent anti-spyware. AVG free from a href="http://free.avg.com" rel="nofollow"http://free.avg.com/a is good, and it does not refuse to load with any traces of McAfee on the machine, which many others do. It also has a very effective safe mode scanner to get to files normally locked by the system in normal.