My monitor keeps flickering on and off every few seconds, is it my video card?

I would check and make sure all the fans inside your computer are working. It might be overheating. Did you add anything new to your computer before this started happening? Maybe your power supply is being overloaded.

When you say “It freezes up the screen,” do you mean your operating system is frozen?

Try changing the refresh ratio of your monitor. Did that help?

The fan on the video card had stopped (4 year old video card). Got a new video card and all is good now. Thanks for the help!