I see in your other topics you mention previously having a malware infection. This is probably the root cause of the problems you are having. Certain malware can cause programs to not work, install, update, etc...
Even if the malware is gone (I suspect it is not), it can still render your system unoperable and/or unstable (hence the unexpected shutdowns).
Please create a
in the Am I Infected
sub-forum with a thorough description of the problems you are having (programs won't run, can't install AV, etc..). A Malware Response Team (MRT) member will get to you as soon as possible and begin the disinfection process. Please be patient as the MRT is always overwhelmed.