Problems Connecting to Wireless N-Router WNR2000v2

[Octopete]

So here is my problem, I just built a Windows 7 64-bit computer for my sister, it uses a Sabrent Wireless-N PCI adapter and I am trying to connect to the internet using a Netgear Wireless-N WNR2000v2 router. The problem is that her while her computer will detect the router I am unable to connect to it, or when I do manage to connect, it drops that connection a few seconds afterward.

Her computer will connect to other routers with no problem, and her laptop and mobile phone will connect to this router without any problems. I tried doing a hard reset of the router, and I installed drivers for the network card, but neither of these helped. Any ideas of how I can fix this problem?

 

[Guest]

Check the router's settings. Wireless mode may be set to G only, though that shouldn't be a problem.

Access List (exclude or include by MAC ID) might be enabled.

 

[Octopete]

Best answer selected by Octopete.