Internet locks up with router... always after a reboot

[souton]

hi I hope someone can please help me. I have a d-link wired router and I set up a manual IP for my xbox360 and my PC. It ran smoothly the first couple of months. Now I will lose connection on xbox and my PC internet connection will "lock-up" a lot. It will stay frozen for a couple of minutes before working again. I've googled and googled but just find people with wireless problems. Also, if i reboot the router/modem, the internet will work for exactly 60 seconds and then freeze for minutes. It's a real pain. Does anyone have any idea whats goin on? Do I need a new router? Soon I should be getting a whole new PC and router but I still want to know what's goin on cause I can't find any answers. thanks!