Black screen crash graphics card?

Hi there, whenever I play a game- but more intensive types rather than a trivial game/online one etc, after a certain amount of time which can vary- from 20-60 minutes etc i eventually get a immediate sudden black screen appearing on the screen, completely freezing my computer and having to reset to start up again, aswell as getting a message of windows shutdown incorrectly.

Also with this comes a very loud high pitched buzzind/beeping sound for around 3-4 seconds. When I try windows event viewer (new to it so only know how to do basic functions) it mentions this:



"Custom dynamic link libraries are being loaded for every application. The system administrator should review the list of libraries to ensure they are related to trusted applications."

"Crash dump initialization failed!" on two seperate occasions within the same 5 seconds,

"Audit events have been dropped by the transport. 0"



all of these within the same :39 minutes past the hour, so obviously related. Has done the same thing, and same event details four seperate times, each within an hour of eachother.

The game I'm noticing the problem now on in Lead and Gold, a steam based shooter game. I've also noticed the problem on other games too, aswell as non-steam ones, so the problem is possibly not just down to steam.

I have a radeon hd 4870 card, quad core amd processor, gigabyte MB, 4 gig ddr3 1333 kingston ram, 1/2 tb harddrive, and a 650w good brand corsair powerpack. So my system is definately capable its definately an issue/error occuring somewhere.

Any help would be greatly appriciated, if anyone has heard of similar problems along these lines. Thank you,

Alex