I have a windows 7 computer connected to the hot spot network. However I cannot connect my Windows XP computer to the hot spot network. Windows XP reports the network adaptor is functioning properly and I have set the network connection for DHCP and WPA AES security and entered the passphrase.
What error message are you recieving on your WinXP machine when trying to connect?
Connections can fail for any number of reasons. Chances are good if its an XP machine that the passwords are not matching up in one way or another. Perhaps you have duplicate wireless profiles saved to your machine that are conflicting with each other.
A good experiment would be to remove the wireless password on your MiFi temporarily. If you can connect without a password then you know for sure its a password issue. Delete your wireless profiles and start over again making sure to carefully enter the password. If your XP machine cannot connect without a password then there is a hardware problem either on your MiFi or the network adapter on the XP machine. The older XP machines only support WEP security on wireless networks. You should make sure you are updated to the latest Service Pack to make sure your XP machine understands the WPA and WPA2 protocols.