malick4132
The information in the following post my help:
http://en.community.dell.com/support-forums/desktop/f/3514/p/19508340/20372002.aspx#20372002
Don't go too cheap on the power supply, because it is one of computer's major components.
This Corsair 500w PSU would be fine:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139027
Bev.