But there is something free that you can install in a couple of minutes that may well give your computer a boost when using the internet. How much? No guarantees, maybe nothing, maybe 10%, maybe 20% depending on what you are doing. It is a small program called Flashblock (Google it). It is available for the Firefox and Chrome browsers but not for Internet Explorer, so you should switch to one of those if you haven't already done so.
As its name suggests, Flashblock works by, er, blocking Flash. Flash is used by many websites to display adverts, show pointless animations and so on. All of this stuff eats up resources on your computer, making the internet experience slower. It all depends on the particular website, but it can bring a slow computer to its knees. Flashblock stops all of this and puts indicators on the webpage to show what it has done. If you need to see the Flash - which is a perfectly legitimate requirement on many websites - just click the indicators to enable it again for that page. If you are a little bit technically minded, run the Windows Task Manager and see what happens before and after. It can be quite an eye opener.