Installation causing explorer.exe to not intiate

Hey everyone. I had looked around and saw no topics that fit exactly what happened to me. So if there is a topic about this, I apologize.

Okay, so I was running the Prerelease build of Windows 10 (the Devloper Build) and I was running mcafee. It stopped working and they gave me a severe copout answer (it’s not compatible with that version). So I went and downloaded Comodo cause I used it on prior computers. Once it installed and said it needed to restart, on the restart all I got was a black screen and the comodo widget on my screen. Windows Explorer (explorer.exe) would not restart or initiate, and I couldn’t get anything to run on the system.

As of right now, I am doing a full reset on my computer assuming that something messed it all up from me trying to test/repair a family members hard drive. But I need to ask: what went wrong and how can I correct that in the future?

Thanks in advance guys.

EDIT: What can I do in the future if this happens again when I reinstall Comodo?