New
#21
If you reinstalled why don't your Restore points work now? These are necessary to fall back on for situations exactly like this. Turn on System Protection and apportion more space if possible: System Protection - Change Disk Space Usage
You have the driver back to default placeholder given during install Standard VGA. Now the next step which apparently has been overlooked is to see what driver Windows 7 wants by enabling Automatically deliver drivers via Windows Update (Step 3) then running all Important and Optional Updates except Bing. There may be patches needed as well as drivers to make your hardware run right.
Only after all Updates have been installed with requested restarts, and you go back to Check for Updates and there are no more offered, should any drivers missing in Device Manager or Standard VGA display be imported or updated from the Dell Support Downloads webpage for your tag number. I'm sorry but I don't see where that was done. If there isn't a Win7 driver then try Vista.