HELP ME!! BLACK OUT!-[XLR]Angel

I Am SICK of this Black Out thing. Once i join a room, after a few minutes later, my computer screen turns all black. U cant see ur cursor or anything and then u hav 2 hold the power button for force shutdown. Is this normal? I cant play anything on CF now.. Does anyone hav the same problem??
:O

~[XLR]Angel
PLz HELP ME!! :'(