I took a look at the specs for your computer and every thing I've seen showed your model comes with 6000 series card and not the 5700 series.
Copyed this from the specs posted on Cnet.com
- AMD Radeon™ HD 6450 1GB DDR3
- Nvidia® Geforce® GT530
- AMD Radeon™ HD 6670 1GB DDR5
- AMD Radeon™ HD 6770
- Single AMD Radeon™ HD 6870
Try rolling back to your old driver so that your system is running as before.
Go to run type in dxdiag.exe, click on the Display tab and that should tell you what Graphic card you have.
Down load any new drivers for your card from Dell, as your model is no longer sold. Your drivers might be out dated. If so, then go to AMD and down load the drivers for your card. Uninstall the driver from your system reboot and install the new drivers.
I see you did roll back your system, so just type in the dxdiag.exe.
GA-MA-790X-UD4P, Phenom II X2 (unlocked B 55), 2x2GB Super talent 2x1 Super Talent (6GB), LG DVD/CD burner, 1ea Hitachi/WD HD 250GB, Asus EHA5770 CUcore 1GB, SB X-FI Titanium. Antec EW750 PS, Antec 900II case