I had a MiFi 2200 from Verizon before and it still connects to the xp computer with the wpa tkip setting. I have changed the MIFI 4510L to the wpa tkip using the program and I can connect my windows 7 laptops, my Motorola Droid, my printer and my Palm TX, not all at the same time, with no problem. The xp computer will not even see the 4510L. If I turn on the 2200 even though it has no internet connection the xp sees it and connects fine. I am totally stumped. Windows XP professional version 2002 Service pack 3. I even changed the 802.11 from n/g/b to just g/b and still can get the xp to see the MiFi 4510L.