dlink router

[Clarkvcr]

Hi, I've got a dlink DIR-615 router and having a problem. My main desk top is wired through it and works fine. A remote desktop (8 foot away) can't get connected to the internet, nor can a laptop in the house. I have reinstalled the router and wireless card and although the remote pc recognises the router it has a bad internet connection, as does the laptop.
When I sit the mouse over the icons on the remote pc it's strength is 1 Mbps whilst at the same time the wired main pc is at 100 Mbps. I'm going back to the shop I purchased the router from tomorrow, just wondering if anyone had any thoughts. Ta.