Problem when loading up computer

This screen showed up one day. I don't know what it wants me to do.

I've tried restarting it but the screen comes up every time.
I am fine with taking it to a computer guy if it will be a bit tricky to do for an amateur. Just want to know if there is an easy way to fix it.

PS. There are files on the computer which I would like to keep.

Welcome to the forum do you have an install DVD or USB you need to boot from that and run a repair