A week ago I upgraded my CPU from Intel C2D E6300 to E8500. My brother tested over clocking combinations on his account on my PC while I was away. When I returned and tried to log on to my account I got a black screen. I could move my cursor though. CTRL-ALT-DEL and other keyboard shortcuts have no effect. So basically, I have to restart with the button. Strange thing is, I can enter my brother's account and it works fine. I can also log in to my account when using Safe Mode.
Tried everything like restoring from disk, reducing overclock, removing E8500 drivers and re-installing them. Nothing works.
Motherboard: Asus P5Q PRO
CPU: Intel C2D E8500
GPU: Leadtek GTX260 Extreme plus
PSU: OCZGXS600w + Thermaltake Power Express 250w(for my hungry GPU)
RAM: 2GB Corsair dominator DDR2 1066mhz
Windows 7 Ultimate 32 bit
This problem is very frustrating so any help will be appreciated.