First run a speed test on your internet connection, go to 2wire.com and run the speed meter at the top of the screen. If running noticeably slower than what you are paying for, restart the modem and test again. That is the simple one, from there is may be any number of factors, but you can go to the control panel from start and then find system to see how much RAM that is present. Antivirus programs are a double edged sword in some cases, they protect from rogue programs that can slow your machine and many at the same time slow the process time in that protection mode.