i have just some days back installed the older version of the mcafee, during installation itself iwas showing something relating ot incompatibility, still i completed the process but later i realised it didnt got installed completely and there are issues with it now.
I want to completely uninstall it from the system.
Assuming it's the home products we are talking about and the version is more recent than 2005 try this....
Uninstall in the normal way via Control Panel/Add or Remove Programs (XP) Programs/Uninstall a Program (Vista/Windows 7)
Run the Removal Tool (MCPR) linked in Useful Links at the top of this page.