|If it will boot up at all you can try installing drivers but if not then you will probably end up reinstalling W7. MS says you need to reinstall. If factory install of OEM version, you may need a new version, especially if the factory restore does not work.|
As far as the power supply is concerned, you have not supplied enough information. If everything else is the same then the power supply should be fine, but if you are adding or changing the graphics card then all bets are off. You need to supply detailed information on make/model of graphics card, power supply, and all significant components. Make special note of how many 12 volt rails and the Amperage on each rail from the specs or label.
You have to be a little bit crazy to keep you from going insane.