Radeon 9550 monitor shut down

I just installed an old game (Axis and Allies) before I could play it my left monitor shut down (no signal I think). I checked the properties and the option for two monitors was gone. I rebooted and then my other monitor wouldnt work after the startup screen (yellow light).

I did a fresh install of windows xp and before I could install the drivers for my Diamond Radeon 9550 card, the other monitor flashed and shut down also. I installed the default video card that came with my computer and now it works with only one monitor.

I have a Dell Lattitude 4600 with the original power supply.
Im running two 250gb hard drives and a sound blaster audigy sound card.
I have 1 Gig of memory and my computer is a 2.4 ghz Pentium 4
Two dvd/cd r/rw.

Does anyone have any idea why the graphics card keeps shutting down. It will shut down one monitor then the other. I still havent been able to install the drivers because the screens shut down before I can get to it.

Any Ideas will help.
Thanks
Ray