well, the specs arent shown for that PSU, but it doesnt matter, MadDog items are Generic peices of Junk.... If you can return it and get this instead: http://www.newegg.com/Product/Produc...82E16817104954
if you have integrated GFX as you say... if its enabled at the same time your 7600GT is, then that may also be your cause of issue.
go into BIOS. (hold witchever button your manual says at POST befor anything starts loading) (manufactuers website may also say)... befor waisting time looking up the button though, the most common are either (delete) (F1) or (F2), chances are its one of those....
once in BIOS, Disable your Onboard Display adapter, or whatever it says... Different BIOSs have there own wording for the option... It may just have an option for example: to switch between Onboard/AGP or whatever.
...you can leave your 7600GT in the computer as you changer those options, it doesnt make a difference.
DO the steops listed in the previouse post/link to remove and install those 8x drivers first, and you shouldnt even need to do this next step -> If the Onboard adapter is disable in BIOS windwos wont even see it... but if for some strange reason it cannot be disable in BIOS, do this -> go to /start/run, type "devmgmt.msc" hit enter.... expand the "display adapter" tab, and /right click/Disable the one that Is Not the 7600GT. (only the 7600GT should be in that tab).