Information about the recent history of what you or someone else has done with that computer might be relevant ! Did you notice any updates taking place, or didn't you see those ?
It could have been a bad DAT update/push. In which case,
http://forums.mcafeehelp.com/showthread.php?t=229135 might have helped.
But since you already uninstalled and reinstalled it: did you use the MCPR tool to uninstall ?
If not, I suggest uninstalling, using the MCPR tool according to instructions on this forum, and then reinstall.
Have you had any other security software (like Norton/Symantec) on your system ? They typically leave leftovers behind which can cause problems later if you don't use the correct removal tool.
Other than that, I can suggest scanning with free MBAM and SAS in case you are infected, maybe an online scan by Kaspersky, and chatting with tech support.
Oh, make sure your time/date settings are correct !