Two possible problems here : one, maybe you do have a virus or other malware, especially if you're operating without any anti-virus protection. And two, if you tried to install McAfee over the top of an existing version then the previous installation's files and registry settings were probably not removed. There's a tool to do this - MCPR - which you should run before re-installing.
(Edited) Possibly also the pre-installation utility - see http://service.mcafee.com/FAQDocument.aspx?id=TS100119.
If you haven't got any installed McAfee product (check in Add/Remove Programs to be sure and click Remove if there's an entry there) then run the MCPR tool. Follow the instructions given in
("How to uninstall or reinstall supported McAfee consumer products using the McAfee Consumer Products Removal tool (MCPR.exe)") - in there is a download link for MCPR.
Before re-installing McAfee you should run a couple of scans, with Malwarebytes (free version) and Windows Live Safety Scanner. Both of these are on-demand scanners; you only have use of the Windows tool for a limited period (8 or 10 days) before it deactivates.
You can't do a system restore to get rid of malware.
Run rkill, small executable, no need to install. READ THE DESCRIPTION. delete after you are clean.