help with left 4 dead 2

[76561198039138599]

what happens is that when I play left 4 dead 2 and mequeda locked and I get out and get back into everything right but when I start the game and the screen goes black and the sound sounds like scratched cd and restarted my pc the only thing can fix it is to uninstall the game and install steam when both the game and steam with copying segurida desframentar works I have tested the game and recently took a little while when playing the controls not workingmy appealwindows 7 32 bitpemtiun intel dual-core 2.60 ghz2 gb ramIntel G41 Express chipset driver 814