A 7600GT's power usage is quite low anyway and the power supply might not be your problem given that driver message. Do the reboots only happen in 3D programs? Do they occur every time and right when you start the program?
Dunno know what's happening with it right now. Ran fine last night. It rebooted after launching Project IGI and Quake2 this morning (between leaving windows and the game actually kicking in on screen). Manually Rebooted and tried again: same thing. Manually Rebooted and IGI ran, albeit choppy. Rebooted again and reinstalled the drivers and DX9 (from the GPU CD).
Then windows wouldn't start-up. It just froze before the Windows loading screen.
Two things: Hardware device manager states the 7600GT is owrking correctly (ie no repeat of the previous error)
And the pc fails to Autostart. "Disk boot failure - boot from ATAPI CD Rom, insert Boot CD and press enter"
The boot CD has been long been lost so I just whacked enter and boots from the ATAPI, whatever the hell that is.