If you have been using it for a few years ot may be time to re-install Windows (if you are running Windows).
Over time all sorts of thing get added to Windows (new programs etc), slowing it down.
A re-install of Windows clears out all this rubbish and allows you to start again with a "clean sheet".
On the hardware side the cheapest and easiest way to get a speed boost is to add more RAM memory, but it depends what yoru hardware spec already is (which is why ACtheTROLL asked).