9800 gtx trouble

Not sure whats the problem here, just upgraded to 9800gtx from an hd2900pro, i have a 550w antec psu, the hd2900pro overclocked to xt speeds ran fine, but now with this 9800gtx my computer seems to lock up for 30 seconds and wont do anything when i alt tab in and out of games. Anyone know what could be the cause of this?

When i click on Manage 3d settings in the NVIDIA Control panel, it also locks up, Mouse doesn't even move either it just locks up the whole computer.

Was going to say, it sounds like driver issues. With how new the card is, I'd be weary of the drivers coming out at first. Newer drivers will probably alleviate these types of problems.