I was having issues connecting to the Internet with my Windows 7 laptop using the MiFi 2200 as a WiFi device.
My WiFi adfapter was retaining the last IP Address it had obtained ... in my case my home network.
Go to a command prompt and do an ipconfig -release followed by ipconfig-renew.
It pulls an address from the MiFi from the DHCP range and works perfectly.
Hope this works for everyone!