My roommate has a Dlink WBR-1310 wireless router. Before I moved in she was using it without encryption. I convinced her to add encryption to the line and successfully added a WPA password to it. My desktop (WinXP) connects to the router with no problem at all. My roommate's iBook (C2D, OS 10.4) will systematically fail to connect to the router every couple of days. The AirPort icon at the top right of the desktop indicates a full signal but nothing that uses the Internet will work. The solution I found was to unplug the router's power cable and the ethernet cable that goes from it to the cable modem; wait a few seconds; plug in the power; then plug in the ethernet cable. This will reset it and it will work for a while, before falling back to the same problem.
Though this problem did not exist while there was no wireless password I obviously do not want to keep the password up. I checked the relevant settings in the router and on the computer but cannot find any obvious problems. A Google search and a search of Dlink's website turned up nothing useful; there are a few threads that deal with the problem but no answers.
Any help troubleshooting this will be much appreciated!