It definatly sounds like a router issue. Is it up to date? Do you have the drivers
for it installed on your computer? What about the ethernet cord your using? Any cuts, fraying, or damage? Also, try hooking it up and using it as you normally would. Are the lights bouncing on and off at an extremely fast rate on the router? And hook up the old router, and play a movie/video. Then play the same video on the new router. This will give you a better feel for if it is your computer, or the router.
Let us know,