How do you describe this? Hang? Freeze?

[Slaymate]

Yup, I uninstalled the ATI drivers as well; although checking back at Device Manager, the default integrated GPU was listed under Display Adapters (before installing the new drivers)

You have to disable the Integrated ATI GPU and uninstall all of it's drivers. If it appears in Device Manager then it's not disabled.

 

[MindoverMaster]

Yea, Slay. You need to remove ALL of them. Uninstall from programs and driversweep. Disable onboard in BIOS.