Unexplained intermittent lagspikes?

[Orpheus]

I have an issue with connecting to my wireless router using the wireless card in my desktop. When I try using the Linksys Wireless Network software, it never can obtain an IP address at all. It'll just fail outright and keep trying to connect but fail. When I use the XP Zero Config Utility, it connects, but the lagspikes I get are so terrible I often freeze up online for 20-30 seconds at a time, and it's constant too. The router is using a 64-bit WEP address, and the router is a WRT54G2 v1 Linksys model. The wireless card in my desktop is a WMP54G. I have yet to find any sort of fix to this at all. There's just no logical explanation on how to fix this load of bull****. I've even went far enough to update graphics drivers, sound drivers, everything. I don't have a [bleep]ing clue what is wrong.