Yesterday, I replaced my Radeon HD 7450 card with a Radeon HD 6850 in my new computer. The computer hadn't been installed before, it was new- straight out of the box. Everything was running fine yesterday, but today I am unable to boot up my computer fully. I get to the log-in screen in windows, and after that I get a brief flash of the blue screen of death, then to a screen asking me if I want to start in safe mode. I'm unable to get to "normal" mode at all. After installing the card yesterday I did put in the disc that came with the card, and the drivers were installed. However, I didn't specifically uninstall the old drivers, thinking that the new ones would automatically cancel out the old ones. I'm wondering if that is the cause of my computer not being able to function? If so, how would I check to see if my old drivers are still somehow in my computer and remove them?
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I'm not sure if it would solve the problem but there's no harm in trying. To remove old drivers try this http://btoforums.com/showthread.php?t=2806 I'm sure there are other ways but that's an easy to follow guide
I would be looking at a hardware issue 1st if you BSOD. Whats the rest of your system specs? including PSU