I have my Nexus One configured as a portable Wi-Fi hotspot named AndroidAP JD. Whenever I turn on the wifi capability and connect to it with a Windows 7 machine, it remembers the password and connects automatically. However, it will prompt me to ask if I should make "AndroidAP JD n" a work, home or public network. Why does it make a new network profile for the same hotspot?
Windows does quite a bit of guessing when it tries to identify "which" network it is a member of. The most common of which is using the mac-address of the default-gateway. If the MAC of your default gateway changes... it will prompt you again to identify your network.
Some portable-hotspot apps make the android-device behave as the gateway, while others pass on the gateway directly to your telco's default-gateway(s). In the first case where your phone is acting as the gateway... these are usually apps you can find from 3rd parties (like the android-wifi-teather app.) In the other-case, these are usually limited to apps provided by your telco... so they can track your tethering-usage statistics & such.
If you switch to the 3rd-party app option, your default gateway will remain a constant and Windows will be happy. If you wish to stick to your telco's app... You'll have to keep adding the network until it has added every possible default gateway your telco might have.