Slowdown

A few weeks ago I noticed a hangup that varies from a second or two to several seconds every time I went to another web page. Ok so I thought I've probably got a virus of some kind. My computer is still very functional but I'm getting kind of tired of the slower speed and would like to get it back to the way it was. What I can't understand is that I'll get these hangups even when information is not being exchanged from the internet. No updates of any kind on these web pages but when I go to click on them I still get the delays. I wasn't aware that moving from window to window of already downloaded websites would demand so much from the processor and create an opportunity for a delay