Check the power supply is adequate. Last time I upgraded my graphics card I was assured the PSU I had (around 500W iirc) would be fine.
I had the exact same problem from the start with nvidia gtx 550ti. What solved the issue was downloading a program called MSI afterburner and lower thepontfirebird73 Today, 03:10
Ok, restarted and turned settings to high from v.high, no more crashing. Happened 3 times in quick succession before that. Computer had been on all day,Hurrikane Today, 03:09
omg wow what a great club!dcm Today, 02:32