First off, completely uninstall the nVidia Drivers for the GTX 260 before doing ANYTHING ELSE.
Search for the graphics drivers manually -- I find the Auto-Detect can be problematic sometimes.
- Drivers + Support >> Drivers + Download Center
- Select the type of system you have >> Desktop Graphics
- Select the product family your product belongs to >> Radeon HD Series
- Select your product >> Radeon HD 7xxx Series PCIe
- Select the supported operating system that you have>> *Whatever Operating System you are using for your computer*
- Download the latest NON-BETA Catalyst Software Suite (currently version 14.4 dated 4/24/2014)
FX-8350 @ 4.8GHz // ASUS Crosshair V Formula 990FX // Sapphire Vapor-X HD 7970 + Dual-X HD 7970 // Thermaltake Frio w/ push-pull (using Antec Formula 7 Nano-Diamond + Cooler Master JetFlo fans) // 8GB (2 X 4GB) G.Skill RipJawsX 2133MHz // Corsair TX850 850W // Corsair Force GT 120GB SSD (OS) // Kingston V200+ 120GB SSD // WD Caviar Black 1TB // Windows 7 Ult x64