How to speed up your computer

As for deleting useless things, go to Start>Control Panel> Network+Internet Connections>Internet Options. Then go to where it says browsing history and click delete. It'll give you an option of deleting many things. I would say it's pretty much mandatory to delete the temporary internet files, cookies, and internet history. Everything else is optional. And even though this might be small, it can make the difference in Maple Story between lag and disconnect.

Ccleaner basically does that.