My internet connection keeps dying?

For about a week and a bit my internet keeps disconnecting for about 5 minutes then it would be great for like 30 minutes then start disconnecting again (sometimes it doesn't disconnect for an hour or two). This isn't happening to anyone else computers or laptops in the house. Also during the time it disconnects the game I play (runescape) it starts with just slow responses when I click somewhere but it builds up to the point where the internet connection drops (then it goes back to normal). If it helps A few days before the problems began I factory reset my computer, does this do anything to firmware or something I read about? My computer is also upstairs whilst everyone else is downstairs (the router is downstairs as well). However it's been upstairs for a few months and not had any problems like this. Any ideas? Thanks