Questions about Power

Hi everyone, I have a few questions.

I've been running on an Ultra 600W power supply for a good 3 years now. I was wondering If I should upgrade to a new one...

Everything works for the most part in XP, but I also dual boot vista. When im In vista, I cannot, for the life of me, get SLi to work. I have two 8800 GT's which work in XP. However when I try to get it working in vista, I just get a black screen with a blinking line. I had been going through this problem for months, but I just decided to leave it alone and use XP. However, I'm getting annoyed now. back then, some Forum goers had told me that my PSU was too weak. I had scoffed at first, but I was wondering if they were right after. I can now afford a new PSU, so i figured that I would ask again. Specs are as follows

Ultra 600W SLI ready psu
Intel Q6600
2 x 8800 GT's
4 GB RAM
2 hard drives
Asus P5N-D
many...many...many fans to keep it cool...

Thanks!

I agree with geofelt 100%.

I agree also. If it works with one OS and not another, I don't see how it would be hardware related.

Nah, OK i just bought a new PSU for the heck of it anyway. Since the Topic has been switched over to the Nvidia driver issue anyway... I have tried TONS of drivers. Older versions HAVE worked once or twice, but the end result is that the game I was playing was glitched and had graphical corruption. My OS is up to date, so that's not the problem.

To shed further light on it, I select Enable SLI, click Apply, and then Yes, and then the thing freezes (normal) but then it goes to a black screen with a blinking line in the top left... And then it goes back to desktop with everything functioning EXCEPT for the control panel. After being frozen for about 20 seconds, it crashes, and it virtually deletes itself from the computer, with no record of it ever being on there. I've been trying on and off for months, and I'm getting really annoyed. Any ideas?

Thanks for the suggestion, but that's not the answer that I was looking for...