I would crash a lot with F1, but more recently I get crashes when tabbing in or out, not to mention whenever I start watching something on the TV, be it my own TV, or if I run past some bored SWAT team in the PD lobby watching a video after I waited twenty minutes for a cop slot.
I also just get the occasional random crashes, driving, running, talking, doing nothing, etc.
Oh, and the occasional crash when talking to car dealer, test drive NPC, etc.
All of my crashes never have a notice thereafter, just, desktop, nothing else, as if I had pressed Alt & F4.
Never mind, recently my crashes have said: CMDLCache Out of Memory