I just received a new desktop with a built-in WiFi card (Windows 7 Home Premium x64). However, I am only able to receive any WiFi signal when the computer is within 1-2 meters of a router. Even then, the signal is very weak (Windows 7 says it is "poor").

I have tried this with 2 different routers and see similar results.

I have somewhere around a dozen other devices that can connect to both routers with greater signal strength (usually full strength) from much, much further away.

When I tried calling support I was instructed to reinstall my drivers and attempt to change the WiFi channel of the router. Neither worked. I was then told that the problem was with my routers and that the computer was functioning normally and that it was certainly not a hardware problem.

What would be the cause of this and is there anything I can do to fix it?