Will it work for me?

I have a desktop computer that is wired and a lap that is wireless. Both are connected by a Modem and a router. However I cannot play videos on my desktop because the video will only run for a few seconds. But if I disconnect the laptop from the router and plug it directly into the Modem I have no problem with running videos. What I need to know is how can I have each computer connected separately Then I would have no problem running videos. Thank you for any help you can provide.

Roary