Straaaaange problem

Hello, thanks in advance for looking into this. I’ve been having a strange problem and am trying to figure out if it’s malware or not. What’s happening is that when my computer is on long enough, where I haven’t shut it down for the day and have been opening a lot of Mozilla Firefox windows, something happens to it. When that point hits, it only gets worse. First the wording on the tabs in Firefox start disappearing, such as “Yahoo Mail”. Then if I want to close it and save the pages I have open to favorites, the prompt that appears, doesn’t have any words on it, so I can’t see where it says “save” or “cancel”. Then nothing shows in my favorites under Firefox. And if I keep staying on the computer, and then try to restart, I get an error saying I have restricted access.
A few times, after the computer started going downhill, I’ve gotten the Blue Screen of death when I tried putting the computer in standby from my keyboard function button.

Only when I restart the computer do things go back to normal….until it happens again the next time.

I’ve gone through “Read and run me first” up until the point it says to run combofix, without anything being found. I didn’t want to run combofix unless you think I need to.

The laptop is very important and I would very much appreciate any suggestions you may have. It almost seems like the computer is overloading, but the reaction is very malware-like.

Thank you,
Dmitry