Anyone that knows about computers, HELP!

[The G.O.A.T.]

I can start my game. I can even start playing it. As I play, sometimes I get very quick black triangular shapes flashing on the screen. Sometimes the game will freeze during play, like you pressed pause on a vcr, and if I CTRL ALT DEL to task manager and exit, the game returns at the pause menu even though it froze during play, not on a menu. After CTRL ALT DELing so many times and continuing playing, eventually the monitor will just shut off and say digital/analog and another monitor would say no input signal. At first I thought it was the game as I have read about other people having crashing problems, so I have been waiting and waiting for the patch. But yesterday I tried to play Need for Speed Underground 2 and the monitor blacked out again and I had to hold down the power button to turn off the computer. I had no problems with this same computer for 2K10. I even went into NVIDIA control panel and changed the settings to let the application pick the settings. That let the game go longer, but during game play it would turn into like a "negative of a photo" look and switch back and finally froze. I am not a heavy gamer at all, and NBA 2K is always my main and favorite game. I only have problems when trying to play a game. Does it sound like my graphics card is going out? Any ideas or suggestions are appreciated.
Update: Was playing Need for Speed Underground 2, and again it just crashed. The monitor turns off and flashes digital/analog. Of course I updated my drivers, directx, etc. That is always the first thing you do.

Windows 7 Home Premium 64bit
Intel Core i7 860 @ 2.80GHz
8 GB RAM
NVIDIA GeForce GTS 240

[sendoman]

check your VGA and your drivers download the lastest maybe your VGA is goingo out becauseyou see artifacts and your VGA bur i dont know that way i prefer ati that nvidia its cheaper and better