I doubt you've been hacked, my guess would be that your system might have been upgraded to the new version of DirectX and that the drivers it installed for your card don't match correctly. I would probably try to reinstall the drivers you know work for your card, or check to see if there are new drivers (which don't always mean better).
If you didn't knowingly install a new version of DirectX did you install MS CFS3? If so I've heard that it will install the new version without asking first.