I have only 2 games I can't even run, Magicka, as baffling it is, and Orcs Must Die, which would run oh so nicely if it wasn't for that stupid single core CPU problem. All I can see ingame is my character's weapon, well, actually that's all I see of everyone, and even if I hit an enemy the game will just crash.
There's been some problem with Super Meat Boy too for a short time, telling me I missed a directx dll or something, but it magically fixed itself before me going to search for the problem.
And then there's Faerie Solitaire. Whenever I start it up and reach the menu, the PC just restarts. No error message, nothing. It's weird because it used to run just fine.
And then again, my whole steam library is a graveyard at the moment as my PC killed its 3rd hard drive last week. Sucks.