PC crash during the games

My computer crashes every time I start a game Basically, the game plays well, sponsors of the top displayed properly (eg Nvidia, ...).
But as soon as the interface of the game should appear, I find myself with a black screen or a loss of signal.

I had a ASUS P5N-E SLI I replaced by a ASUS P5Q-PRO, 8800 GTS that I replaced by a ATI4850 and G. SKILL 6400CL4D (2 X 1GB) that I replaced by the Corsair Dominator CM2X1024-8500C5D (2 X 1GB)

I have two monitors, Samsung SyncMaster 226BW and a CRT IIYAMA Pro 451. My drivers are up to date, DirectX too. I am using XP Ultimate Edition 7.1

I did the test with two monitors in fact plugging one.
The problem is still present.

You do not need to change processor since it is already very good!

I think The problem is probably with video drivers. Be sure to use the latest version of drivers and especially to uninstall old versions before putting the new ones. Put resolutions and graphics details to a minimum in games to see if the games start properly.

Also take care to use an official version and in rule of Windows XP, the alternate versions nonlegal as “XP Ultimate Edition 7.1” are not famous for their stability and often “are arranged” and “are optimized” with the small happiness.