well you gotta give us details here, but it might be a background application, virus, tray application, and plenty of other things, but almost all in the branches of the ones I listed. PC specs, maybe applications you think can cause it, anything will help us tell you what's wrong. But what you can do first is right click the taskbar and click task manager, look for an application taking up processing power or an application taking up a lot of RAM if you don't have a lot. Maybe your sound card is crapping out if your sound sucks, but you said your typing too so that's what I was explaining.