Desktop (Dimension 4400) Internet connection problems -- things are sloooooow

I have a five year old Dell Dimension 4400 using WindowsXP.  I have Verizon DSL.  About 3-months ago a warning box started popping up on the lower part of the screen:  Local Area Connection, a network cable is unplugged.  It would occur about every 15 minutes or half hour while I was on the Net.  It never showed (shows) up when I don't have IE open.  Then I noticed that my Net connection started to get slower and pages would start timing out and the warning box would pop up more frequently.  Now my connection is ten-times slower than dial-up:  downloads stall and time out, I enter data and lose it when I hit enter, I often have to try multiple times to get to a page, etc.  And the warning box pops up almost four or five times a minute.

 

The Windows diagnostic says that there is a problem between the modem and operating system.

 

Verizon pinged the modem and claims that it's working.  I replaced the Cat5 cable between the modem and OS with a new Cat6e patch cable.  I replaced the Ethernet card with the same type from Dell.  I tried different permutations of all of these to no avail.  I made sure all connections were solid and all the cards are seated properly.  While I had the tower open I also blasted some air in the crevices to clean out any possible dust or dirt.

 

I went to Settings>Control Panel>Network Connections and got the screen with the LAN or High-Speed Internet icon/info.  In between the lines Local Area Connection and CNet PRO200WL PCI Fast Ethernet Adapter is the status line.  It changes from Connected to Network Cable Unplugged to Acquiring Network Address every few seconds.  I right-clicked and disabled and then renabled the connection and it didn't help.  I right-clicked to Repair and got the following messages:  "Windows is taking the following actions:  Renewing your IP address."  Then "Windows could not finish repairing the problem because the following action cannot be completed:  Renewing your IP address.  For assistance, contact the person who manages your network."

 

All non-Net functions I use (Word, Excel, Photoshop, etc.) have not been affected.

 

Any ideas?

 

Thanks,

Tim

P.S.  I'm at the public library right now because every time I try to log into the Dell Forums I time out.