I purchased the Zonet ZEW2500P wireless USB adapter to replace a wireless adapter that repeatedly dropped the connection throughout the day.
Installing the Zonet adapter on my Win XP computer was easy and straight forward. The only decision required during installation is whether to install the RAlink configuration tool or the Microsoft Zero configuration tool. I chose the RAlink configuration tool which is the recommended option.
As of this writing the Zonet adapter has been excellent with no dropped connections.