Launching multiplayer and getting Blue Screen of Death (BSOD)


I’ve been playing Garry’s Mod on my computer for some time and now every time I launch Garry’s Mod multiplayer, my computer gets a blue screen of death.
I haven’t changed/replaced anything inside my computer and my display drivers appear to be up-to-date.

I’ve been reading other forums that have the same issue and they said to try setting the launch options as:

"+mat_bumpmap 0 +mat_picmip 2 -dxlevel 80"

That didn’t work.

Here are my computer specifications:

OS Name Microsoft Windows 7 Professional
Processor AMD Athlon™ II X3 440 Processor, 3000 Mhz, 3 Core(s), 3 Logical Processor(s)
Installed Physical Memory (RAM) 4.00 GB
Display ATI Radeon HD 5800 Series

EDIT: Single player works perfectly fine, I have no problems when launching with single player.

Any help is much appreciated!

Have you tried the following?

-defragmenting the game cache
-validating the game files
-reinstalling GMod
-Removing said launch options (if you haven’t already)
-completely reinstalling Steam

Games dont usually make the whole system crash… But I’ve been wrong before.