You need to determine whether is your router or your cable or dsl modem.
Connect your PC directly to the modem and see if this happens. If it still does, it's between you and your internet service provider.
If it doesn't, replace your router.
I do not have a seperate modem, i just have a wireless router i am guessing the modem is built in. I have tried plugging it in using an ethernet cable before but this did not make any difference. Any other suggestions?