then it must be a physical problem.....
try restart button...
we need a psychiatrist of computer.
Try system restore
restore to the point when it was working fine and hope that it will work.
than save ur work and format ur C disk again and download the NOD 32 antivirus (trial version)
and go to
nod321.com
u can get username and PW there and it will be updated regulalry. and it works better than mcaffe.
GL
I did restore / recovery disk / BIOS update.....
BUT
problem is still there, restart by itself 15 sec after shut down