Is it a video problem?

Could be anything. No post at all would be more likely a MB or Power problem though.

Most modern motherboards won't post without a CPU or memory. Used to be a day when you could get a beep code for lack of either . Some still ahve a whaling beep if there is nothing in the socket, though it is not particualrly common anymore.

I can get a black screen of no activity with a bad OC anywhere in the system. It really could be anything. Make sure to follow the insructions for your MB exactly when resetting cmos, some are different/take longer dependign on how the jumper/battery is set up.

If you are sure Cmos is clean and you still get no post at I would normally debug Power > Memory > CPU > MB > Expansion Cards.

If you remove the video card and everything else works it will still post (if you have a speaker you will hear the beep) so absolutely nothing is almost never related to the GPU unless it is shorting something else out.