There are too many factors involved here ! First you have told us nothing about your laptop. How old is it, for instance ?
If you haven't done a defrag for a while, you should try that first. Its easy to do but it will take quite a time...perhaps overnight is best.
There are lots of reasons why its running slow.
Is it happening when you are "off-line" ie, not connected to the 'net, or is it happening when you are surfing ?
What kind of download speed should you be getting ?
Has it suddenly started going slow ?
Sorry but too any imponderables to help very much ! The good thing about laptops these days is that they are so cheap compared to years ago, if you do replace it, it won't cost you a fortune.