renewed McAfee and next day noticed it was not running and could not connect to internet.
Removed HD and scanned with another computer, Norton did not find anything. Ad-Aware PRO found a Trojan (\AppData\Roaming\Protector-ihjj.exe) and removed it. Re=installed HD in computer, still could not run McAfee, installed CCleaner and cleaned lots of entries.
Still could not run McAfee.
Uninstalled McAfee an install MS Security Essentials, it would not run either.
Installed MalwareBytes Anti-Malware and it would not run either.
Tried AVG next, didn’t work either.
Could not repair file associations either.
Finally read a post (from Dmac24) and downloaded SuperAntispyware, and it ran. It found 1539 threats in registry entries:
HKLM\software\Microsoft\Windows NT\current version\image file execution options\ {filename}.exe that was preventing all of the antivirus program file names one could think of from running, plus other system program files like regedit. Now MBAM, MSSE and regedit are all working.
My hat is off to SuperAntiSpyware. It solved the problem in 10 minutes after I spend 10 frustrating hours working on it.
I don’t know if the Trojan changed the registry entries or what, but thanks to Dmac24's post that led me to download SuperAntiSpyware. I ran MBAM next and it found another Trojan.BHO registery key = HKCR\.fsharproj
I hope this helps the next person.
JayBirds
PS: Don't know why I could not post a reply to Dmac24's entry on same subject.