Windows 8 x64 Pro wont login after changing GPU

Alright, this is the case i've been strugling with : Recently bought a new graphics card(NVidia GTX 660) , windows run flawlessly before instaling it(On my AMD radeon HD 4850 and 3870-both worked fine)... after doing it windows booted up until the loging screen normaly-only the resolution was lower-.

Problem: Windows wont let me log in whatever i try ... it stucks at the login screen or it logs in showing a black screen where i can only see and move the mouse.

I tried booting safe mode ... didnt find any problems, selecting to restore to a previous point solved the problem and was able to login normaly.(windows had installed the basic windows display driver) However, after restarting , i was again unable to login.

Details: I dual boot windows 8 with ubuntu. Also read about disabling UEFI option i BIOS but it already was disabled...

Also i was once able to login(not by restoring) so i installed the nvidia 310.90 driver and worked fine( played different games far cry 3 , call of duty ... it was generaly working with no problems) restarting the pc today the problem showed up again....

Would a format solve the problem???

Thanks in advance.

Did you uninstall the Catalyst (AMD) drivers before changing graphics cards? Sounds like you did not, if you can boot into safe mode.

The usual procedure:

With the old graphics card in place, remove the drivers/control software.

Shut down rather than rebooting.

Swap card.

Start up. The generic Windows VGA drivers may be what installs to run the new card.

Install the new drivers.

Reboot.

Thanks for your reply.

Yes i had uninstalled the AMD drivers... Restored windows again its currently working fine and i hope it stays that way ...

When windows runs into safe mode it cannot uninstall anything because 'windows installer' is disabled ...

The thing is, that whenever that happens windows becomes unsusable, and cant even login when it runs on the integrated gpu of the motherboard, so the only option is to restore...