Connection dropped routinely

I am running a Dell Inspiron 8200 With Win. XP SP3. I upgraded to a Netgear
DGN 2000 Router / Modem and also installed an Intel PRO/Wireless 2200 BG
Network Controller. My ethernet connection is a 3Com 3C920 Integrated Fast
Ethernet Controller. It doesn't matter whether I connect by cable or
wireless, after I am connected, the connection is dropped every 20 sec. for a
period of a sec. or two. I get the bubble "limited or no connectivity"
followed by "acquiring network address". It then connects again for another
20 sec. I have upgraded the firmware on the router but can't update drivers
for the Intel card because connection is constantly dropped. I have turned
off firewall settings for Norton Internet Security but it doesn't matter. I
suspect setting issues.