DirectX 11 crashes system

It seems that I have been unable to run any applications that use DirectX 11. The only reference point that I have would be when I got my Radeon HD 6990. Before that, I never really had any DirectX 11 capable software that I knew of. I had a Radeon HD 5770 before.

Anyways, this is what happens: I'll open up a DirectX 11 application, such as Crysis 2 (with DX11 pack and HiRes Textures pack installed) or Unigine Heaven DX11 test. The software will not even load for less than a second. Then, while the screen is black, Windows will report the application as crashed and ask me to close it or check for solution. In the notification area on the taskbar, I'll see a little "information bubble" stating that the AMD display driver has crashed and recovered successfully. Other times, the screen will just stay black like it was after launching the software. Then, the system just restarts. No BSOD, it basically acts like you just pushed the reset button.

The weird thing here is that it is only DirectX 11 applications. I can play Crysis Warhead (DX 10.1) no problem, no crashes, as well as any other games that don't use DX11. I can also mine Bitcoin with my 6990, and have been doing that overnight for two days, no crashes. My system has been stable since I built it at the end of 2009 so I know it's not related to recent additions of RAM or CPU overclocks. None of that has changed, the only thing different is the presence of my HD6990. System specs are as follows:

CPU: AMD Phenom II X4 BE 965, 140W, 3.8GHz
GPU: AMD Radeon HD 6990, XFX-HD699A-ENF9 Rev. 1
RAM: 2X Patriot 2GB DDR2 800, 2X Patriot 1GB DDR2 800, 6GB total
HDD: Seagate Barracuda 1TB
MB: Gigabyte GA-MA790X-UD4P
PSU: Cooler Master 750W 80-Plus Certified

Check your event manager for any critical warnings or errors, and also you could try reinstalling DirectX

Nothing in Event Viewer except for a "System has shut down incorrectly" message, exactly the same as pushing the reset button. Installing DirectX did nothing either. Thanks though, Ace.

Alright, test your system in a Clean Boot state, and run an application/game that uses DriectX11, just to make sure there's no interfering processes. If it works, then there's something on your system that conflicts with it.

Open up a command prompt and type in:
Provide the output in your next post.

I can't guarantee anything, but I'd suggest you run DxDiag from the run menu. It'll do a brief scan and look for issues; check under the Display tab in particular.

try use ComboFix

What Catalyst driver version?