I have 2 lights in my break room and both of them won't turn on anymore. They each have 3 Philips 800 Series T8 fluorescent lamps in them. I switched out the lamps for new one but the lights still didn't come on. Is there anything I might be able to do to fix the issue? Is it mundane, or will I need to get an electrician in to repair something?

Check to insure that breaker has not tripped.

Do you have a meter? If so do you know how to use it?

Ballist may be bad. If you can do minimal wiring you can replace them yourself. Inside the fixture there is a white cover that clips out. Remove the cover and you'll see the ballist. Use a meter to see if there is power coming to it. If there is then switch out the ballist.

As HK said first thing to check would be breaker. It would be every rare for ballasts to go in both lights at same time.

The next thing to check would be the wall switch.

Check