Linksys providing "Limited Or No Connectivity" on 1 of 2 computers

My problem is this.  When I got home from work today and turned on the computer that I most frequently use, it had an icon on the bottom of the screen that said "network cable disconnected".  I checked the connection, and it wasn't disconnected, but I unplugged it and plugged it back in, and the icon changed to "Acquiring Network Address".  After a few minutes this went away and it says "Limited or No Connectivity".  

I run two computer off of a Linksys WRT54GS router.  Even though this is a wireless router, both of my computers are hardwired.  My second computer works fine.  I tried using the Winsockxpfix.exe file, to no avail.  I plugged the cable modem directly into the computer that wasn't working, and after a few seconds it acquired an IP address and everything worked fine.  However, when I plugged it back into my router, it went back to "Limited or No Connectivity".

Because of the fact that my neighbors all liked to piggy-back my signal, I was assigning static IP's to my computers, and had the router configured to only allow my MAC addresses access the interenet.  So I tried a few things to get it working again.

First, I replaced the cable.  Second, I reset my router to factory settings.  Third, I power cycled both the router and the modem.  Fourth, I ran Winsockxpfix.exe.  Fifth, I uninstalled my ethernet card and reinstalled it.  Sixth, I deleted all temp. internet, cookie and history files.  Seventh, I changed my IP settings to automatically obtain IP address.  Eight, I tried plugging the wires in different ports (all of which worked OK on my connected computer, but had the same result on the "Limited" one).  Ninth, I searched around your site for additional ideas.  None of these steps were able to correct the issue.  (Attempted fixes listed in random order)

What I did come up with is that when I changed my settings on automatically obtain IP address, my working computer was assigned an IP address by my router.  Whilst it appears that the computer that isn't working was assigned an IP address from the cable modem itself.  So I went back in and re-assigned the static IP address and DNS server.  The "Limited or No Connectivity" message went away and said that the "Local Area Network Connection" was connected.  Unfortunately even though it said it was connected I couldn't access the internet, and when I typed in 192.168.1.1 I was unable to access the router.  So it appears that both my cable modem and my router are trying to act as DHCP servers.  

I thought that it was my router, and was getting ready to replace that, but if all the ports work on the computer that I'm using to type this help request, than I believe that the router itself is fine, its just an internal setting somewhere (probably the cable modem as I stated before).

I'm at my wits end.  I've tried everything that I can think of to get it to work, and I have to pull a double shift at work tomorrow thanks to some call offs.  I don't have time to sit around and fiddle with this anymore, but I have some family/friends from out of town coming over monday and we were supposed to play some networked games, but now i'm down a desktop.

I'm going to unplug both my Modem and my Router, and let them sit unpowered all night and all day tomorrow until I get back, and see if that resets anything, but at this point my hopes aren't up too high.

Any suggestions or (preferably) quick fixes would be most appreciated.

Plz help.

Thanks, Mike