Okay.......I did some research and found out what the problem probably is.
I do have AVG, Rhonda - and you're right, it's wonderful for viruses and trojans! I love it! But Spybot removes tracking ware from your computer. It's relatively harmless, but it really slows the computer down. The last time I ran Spybot, in December, it found around 100 tracking devises that it could remove. And I barely go anywhere on the internet.
So....it turns out that Spybot is CPU intensive, and one of my fans on my laptop has been running slow lately. Apparently, it's running *just* slow enough that it can't cool the laptop enough while Spybot is running, and it shuts itself down to protect the processors, etc. Thankfully, I found the heatsink and fan that I need on ebay for an excellent deal!