I believe I have a fix to make this connection work and would like to share it with you.
First I will tell you about my setup. I have the WRT55AG router in another room adjacent to my computer with the WMP55AG wireless card. My computer is running Windows XP. For security purposes I have changed the routers password, disabled SSID broadcast, enabled MAC addressing, enabled WEP encryption and use a shared key. With this setup my computer loses its wireless connection every three minutes or so. Frustrated I decided to change some settings, and found one that allows me to stay connected.
OK then, after I connect to my wireless network I immediately click on the wireless network icon and select view wireless connections from there I click the advanced tab. There is a block marked ?use windows to control my wireless network settings.? While I am connected to my network, I uncheck this block and my computer will stay connected for an indefinite amount of time. Unfortunately if you get disconnected or need to restart your computer, you will need to allow Windows to control your connection again, because it defaults to open key authentication and you will not be able to connect if you have enabled a shared key. Then just repeat the process to stay connected. Since I am already connected to my network via a shared key, and WEP encryption is enabled. The connection remains secure and I retain a wireless connection.