computer runs very slow on internet

Test your internet using https://speedtest.net. Test it on different devices. If your results are faster on other devices, the problem is your laptop. If your other devices are slow too, the problem is your internet or wireless router.

If your problem is internet or wifi router, first ask your service provider about your internet plan. If you have 1-10, that is quite slow. 10-20, decent speed. 30-90 is pretty good, and 100+ is very good. If your own results don't match what they say, your wifi router is no good. Get a better one. Before you do that, unplug power from your modem and router, wait thirty seconds, plug the modem back in wait a minute, then plug the router in.

If the problem is the laptop itself, then try downloading wifi drivers, and restarting it. If that doesn't fix it, replacing​ the wifi card should.

If your not sure what all this means, give me the S/N from the modem, router, and laptop. And the speed test results. I will then formulate a more palatable answer.