Windows says I do not have antivirus protection

Hello Rena,
We are sorry to hear that. Please provide us with the screenshot of the popup so that we could analyze the issue more better. Please follow the instructions on the article http://avgclick.me/getscreenshot to create the screenshot.

Help! I think I have a big problem. This morning my Facebook page kept "bleeding" - not sure how to describe it. Scrolling would suddenly result in the picture or text on a page turning into thin vertical lines.
I tried other web pages with similar results, including improper loading. Even this message box turned to lines momentarily when I scrolled back to add something.
Windows is telling me I do not have antivirus protection. My AVG says it is up to date and running.
I was an AVG paid subscriber for years, but recently a nasty budget crunch has sent me back to AVG Free temporarily.
My PC is using Windows 7 Professional, with Firefox.
A friend suggested I try running a Malwarebytes scan, but it will not install, saying I already have that program. I'm pretty sure I don't.
Now I'm starting to panic. Warning - An instruction involving more than three steps will likely freeze my non-tech-savvy brain. Any very patient people willing to baby-step me through this, please?

There is no pop-up. When I go to Control Panel > System and Security > Action Centre, under Security it shows "Windows did not find antivirus software on this computer".
I am concerned the visual problems on my computer plus the Windows warning means I have a problem?

Rena, For your info, just in case that you are unaware, you can post the screenshot here in your topic. Click on 'Answer' & then click on the 'Image' [mountain symbol] & follow the instructions. 
AVG Guru

Hello Rena,
We are sorry to hear that. Please provide us with the screenshot of the popup so that we could analyze the issue more better. Please follow the instructions on the article http://avgclick.me/getscreenshot to create the screenshot.