I noticed this problem about 3 months ago... First, McAfee started saying it was unable to update, and then Microsoft Security Essentials uninstalled on its own. (Yes, I had two Anti-Viruses installed, that was dumb.) I tried reinstalling MSE, but I got the error code 0x8004FF81. I then tried to install Malwarebytes' Anti-Malware, and that also refuses to install. Today, I hope to do something about this. McAfee is uninstalled, and I'm still getting all the same errors with MSE, so now I'm left with no AntiVirus.
I read that the problem was due to registry keys that were added by malware, here: http://answers.microsoft.com/en-us/protect/forum/mse-protect_updating/mse-install-error-code-0x8004ff81/5ac150bf-bf1f-4bb6-a6f3-2fcd1e6a80b4?page=1 So, I attempted to delete the registry keys like they suggested, but if I try to delete them, Regedit says "Unable to delete all specified values." Now I have no idea what to do, and I have tried everything I could think of. I have tried using RegDelNull, RKill, FileASSASSIN, SubInAcl, and the Elevated Command Prompt tells me "Access denied" when I try to delete the entry. I really wish there was a way to just force a registry entry to delete, but nothing seems to work. I'm at a loss here.
Edited by TheSammy58, 14 August 2014 - 02:07 PM.