I have a U300 card that I use on two different computers. Both 4G and 3G work just fine on my work laptop (which runs Windows XP). However on my personal laptop (which runs Windows Vista), I cannot get 3G to work. I reside in suburban area that does not have 4G Coverage, so this is very frustrating to me. When I try to log on, it tries to get 4G, and then reverts to 3G. But when I try to connect to the 3G I get an error message 797. I have spent many hours at Sprint with no resolution only to be told it is my computer and not the card. However I would hope someone at Sprint would have been able to help me figure out how to resolve this problem. Why I am unable to get 3G to work on Sprint U300 card? Please help. Thanks.