No signal error message with new video card installed?

I had a error message that said "no signal" . So I tried a different monitor still the same message. Then I added a new video card and I still get the same message. When I try to load the software I can't tell what is happening because that message still comes up on my monitor? HELP PLEASE???|||try going into safe mode you do that by turning off your computer then when it starts to load press f5 and it will take you to the boot screen were you can choose safe mode.|||Try to delete the first driver you install and reinstall a new one. It might be that there is conflict between the first driver that is not working.|||u bought a bad video card or ur com motherboard is bad u need a new mb its cheper to buy a new com and use your onw hard drive