Wireless access lagtime on Inspiron e1505

I have had this problem since I purchased this laptop. I do not have any lag problems with any other laptops including other Dells and IBM thinkpads (all work laptops). When I am connected directly to my cable modem, I have no issues at at all. The symptoms are that when I click on any web site link, there is a few (sometimes 8 to 10) second lag time before it actually connects. This happens on all sites, on all apps. I have had two laptops next to each other, both accessing the same wireless router, and only this Dell Inspiron has the problem. I have of course called Dell two or three times on this issue and get no help at all - the last guy actually told me to call my ISP and they would fix it. I told him multiple times that it ONLY happens on this laptop so how could it possibly be and issue with my ISP??? geesh. Anyway - now that I'm laid off (boo) I have time to deal with this. Could it be a problem with my wireless card? I went on the Dell site and tried downloading a bunch of driver updates, etc. but nothing helped. I've googled everything I can think of and can't find any answers. Has anyone else had this issue? Does anyone have any suggestions? It is so annoying that I have been working with a cable stretched across my living room rather than use my wireless. Thanks!