I have a Dell 6400/E1505 laptop with 1.86GHZ core duo processor and when I
unplug the power cord it BSOD's and turns off. I can then turn it on on
battery, and it runs fine on battery, plug it in and its fine, unplug it
again and I get the same BSOD!

I've figured out that if I turn off 'Intel Speedstep' in the system BIOS it
works but I don't really want to leave it like this because battery life is
MUCH worse, like 2.5 hours instead of 4.5

Does anyone have any suggestions? Perhaps is there some sort of a speedstep
driver that is needed for vista? I'm running RC1 Build 5600 but it did it in
build 5536 also!