ET problem.

here is the problem:

i connect to a server, everything looks normal
when i join the server, im spec (obviously)
i join a team, and wait till i spawn

then, out of nothing, my screen freezes. I cant do anything, ctrl+alt+del etc doesnt work, and i have to restart my computer by using the on/off button

I tried updating my pb yesterday, and i checked my computer for spyware, but it doesnt work

wtf is this? how to solve it

thanks.


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EDIT: i also installed new drivers, and i even opened my computer and fuckin cleaned it all, and it still doesnt work