Deteriorating performance

[Pocalypse]

I use AVG free. It's fully updated, and scans pretty often, so I don't think I have a virus.

I defragged about a month ago, but I'll do it again to see if it has any difference.
Edit: Apparently my defrag is on a schedule, and runs every wednesday. And it also defragged my SSD, which is bad. Could that cause some of my issues?

Generally, my computer uses about 7gb of ram. I think this is due to prefetch, I can't figure out anything else that would cause it.
When I'm running wow, it jumps to about 10gb used.