I just got a Radeon HD 6850 by gigabyte today and from previous issues I thought I was suppose to put the card in before installing the new drivers or remove the old ones. I put the card into my computer and plugged the vga in and turned the computer on and it started, I told it to start windows normally, then it did the little spinning animation with the loading bar like it usually does then it just goes black and goes back to the original boot up screen when you first start the computer.
I have tried starting in safe mode with networking so I could delete the only drivers and install the new ones but that didn't work, it just does the same thing.
I can access the system repair and have tried the system restore which didn't work.
I am sure the problem lies with me not uninstalling the drivers because stupidly, 2 months ago I did the exact same thing with a different graphics card on another computer. I thought it was time to get a better computer so I didn't think much of it.
EDIT: I also tried taking out the new video card and using the build in one and got the same effect.
Processor: AMD Athlon II X4 630 Processor 2.80 GHz
RAM: 4 GB (3.75 GB is usable)
System type: 64-bit
Motherboard: Biostar A880G+
Power source: CoolerMaster RP-600-PCAR (W600)