I experience EXACTLY the same thing in Vista. I am experiencing it on 2 different Vista PC's, one home premium 32 bit one home premium 64 bit. My WEP password is 10 characters long, I enter it, having to plug my LAN cable in to get Windows to see the network. The wireless button and adapter is enabled the whole time, and as soon as I plug LAN cable in, it connects to LAN and Wireless simultaneously. Then I can disconnect LAN and it will stay connected to wireless, however it gets changed to an 8 character key (which I cannot see or reveal) and it will not connect until I enter the correct 10 digit key again. Just like previous poster, there is another computer on the network, on XP which does not have this problem and does not disconnect nor have problems seeing the wireless network. We are both in the same workgroup, this has been a problem for 2 weeks. I've reset the modem, flushed DNS multiple times, assigned new I.P. addresses, disabled and enabled DHCP, etc. It is of note that these 2 PC's on Vista, are also from Best Buy, however, it also happened with a Compaq nc6400 running Ubuntu with Windows 7 Virtualized. Shawn and I would appreciate some wizardry here to figure out what's going on!
P.S. I would just enter a WPA password, however it is incompatible with my setup.
Thx in advance,