Intermittent Connectivity with XP

I have a Linksys Router WRT54G and a Linksys wireless adapter (WMP54G). Both worked wonderfully with no problems under Windows 98SE. Then I upgraded to Window XP Home Edition and suddenly the card started losing connectivity every 5-60 mins. Time frame between drops is always different but somewhere in the 5 to 60 min range. The signal strength is fine and the card never indicates a problem under Windows system manager. An upgrade to SP2 did nothing to help the problem. Linksys support has not been able to help either. I even purchased anothe card to try and it is doing the same thing. Another computer with an older version of the adapter WMP54G is working fine and never losing connectivity so I am guessing its not a router problem. Help please!