I'm replacing a Radeon HD4600 with a Geforce gtx 650 Ti BOOST. I uninstalled the driver, turned off computer, removed the 4600, inserted the 650 into the PCI and hooked it up to the PSU, tried turning the computer on and it got to the windows logo but wont actually load windows. I tried putting the 4600 back in and it loads up fine. WTF? Is this because I'm switching from AMD to Nvidia?