Garry's Mod Not Letting Me Change Video Settings?

Well, I seem to be having a bit of an issue here, and I would like some help. I try to make mediocre Garry’s Mod videos, and one day, I wanted anti-aliasing turned on. However, when I click on the Advanced settings for video options, all the tabs only have one option, which is the one they are set to. It never used to do this before. It also only has one resolution for me to use, which is my current one. Anyone have any ideas on how to fix this?

This is a question
Not a screenshot
What are you doing

Yes, but this involves me wanting to take screenshots and videos with Garry’s Mod, only I can’t because Garry’s Mod won’t let me change out of crappy settings. It seemed appropriate for this forum.

It’s not appropriate for this forum. You post screenshots in this section, go to the help section.

Alrighty then, I probably don’t need to say this, but admin, go ahead and lock this up. Headin’ on over to the Help section.

What is your graphics card?