CSGO doesn't launch, but everything else does.

Is anyone's game plain not even starting? The process csgo.exe shows up in the task manager, and my name turns green etc, but the game just never starts and the process closes seconds later.

I've already reinstalled, verified cache, deleted the .blob, rebooted, installed graphics driver updates.

Specs: Intel i3-2120 @ 3.3GHz ; 4gb ddr3 RAM (my other 4gig stick died a few days ago) ; Radeon HD 6570