My PC and Router don't seem to like each other.

Context:  Dell Inspiron 530-104m (new Sept, 08); Win XP, as preinstalled, kept fully updated; ISP: EarthLink DSL;  Modem: ZyXel P-660R-D1; Router: LinkSys BEFSX41 (circa 2003).

Timeline (may be important):

~ 2000, Gateway Computer, got hooked up to MindSpring (subsequently bought by EarthLink).

~2003, bought Router, hooked it up, worked fine.

~2005, switched to homebuilt PC (with Gigabit Lan onboard), everything still worked fine.

April 2008, modem died - replaced with current ZyXel from EarthLink.  NOTE: while trying to diagnose modem problem, I disconnected the Router - and did not even try to use it until now.

Sept. 2008, replaced homebuit PC with DELL Inspiron 530 - I've subsequently added a 2nd hard drive (Hitachi 500 gb SATA), and upgraded memory from 1gb @ 667 mhz to 2gb @800mhz.  Works fine.  I simply plugged in the modem, and awy we went.  I've done NOTHING with drivers or network settings, since what I had worked fine.

Today - got around to trying to hook up my router.  Disconnected the ethernet cable (PC > Modem), and plugged it into the router. 

At this point, I SHOULD be able to log into the router's built-in configuration webpage (http://192.168.1.1/) and set it up.  However, the PC and the Router are having trouble talking to each other.  IE 7 says it can't disply the web page.  XP keeps throwing up a balloon evey 10 seconds or so "a network cable is unplugged", the Router's lights for that port fliker and go out in synch with the balloons.  Same result on all 4 ports.

At first I thought the problem was the router - I chatted with the LinkSys support folks, and of course they think the router is bad and I should buy a new one.

However, the router wakes up just fine and displays its configuration page, when hooked up to my friend's laptop!!!!  So, the problem seems to be MY DELL I530. 

How do I go about analyzing and fixing this problem?

ScottM