My Computer

Agreed. Kaspersky is awesome. The only problem is that you have to pay for it. If you're stuck using Free Antivirus programs, get AVG or Avast. They function best for their price.

How much RAM are you using at standstill? If you don't know how to see, fire up Task manager and look at the bottom, where it'll give a percentage on how much RAM is used. If you're using more than 50%, I suggest upgrading.

Well, I've tried both Avast and AVG before. Didn't like it much.
The ram I'm using usually fluxuates around 2%~20%.
If I click a link or copy files or anything, it quickly hits 100% and then reduces back to 2%~20%.
Quickly as in only lasts 1 or 2 seconds.