Just decided to put in a "newer" graphics card msi radeon 6850 to replace my radeon HD 6670 graphics card. After turning the computer on I get a no signal on my monitor whether i am using VGA or HDMI. So I decided to revert back to the old graphics card and now its not working with that one either. So I am having to use the motherboard's graphic pluggin. which is really slow and basic. Any thoughts on what the problem is?