Connecting a machine to a HUB as well as the cable modem is invalid and dangerous. Are you sure you have such a setup?
Have you tried a different port on said HUB?
Some ISP's lock your connection to the MAC address you have. To reset it, they used to have you call in. But with so many calls, they changed that so that 24 hours and it would auto-reset. A dumb hub could be used at first, then they silently change to a more stringent policy and you'll need a Linksys NAT capable router for it all to work.
An in closing, is the machine free from all Parasites? Many will alter the TCPIP stack and wreck havoc on machines. The five scans I note at http://reviews.cnet.com/5208-6132-0.html?forumID=32&threadID=1313&start=0 and a HijackThis log file usually find if a pest has made its way onto the machine.
OK, I am running Windows Xp I have comcast cable internet. Yesterday I turned on my computer to no internet service. I have had no problems with this connection for 4 years and now, no access to e-mail or the net. I have a hub connected and I then tried connecting to our Xbox Live and Socom 2 through the Hub and it worked no problem. I also disconnected the hub and connected the computer directly to the modem (Surfboard modem) to no avail. I have an old Compaq and connected to the modem and hub with no problems.
AFter doing all of this and 2 calls to tech support that got me no where I decided that my Ethernet card must have went kaput. THe card was a Intel(R) PRO/100 VE Network Connection. I tried rolling back teh driver, uninstalling and reinstalling teh drivers and was unsuccessful. I went to he store and bought a new card. I disabled the first card. powered down the computer and installed the new card. As soon as the computer recognized the new card I had internet! Whoo hoo! But.....
Now I lose my connection evey 5 minutes or so. When I lose the connection if I go into the Local Area Connection Status / Support and click repair, I get my connection back. Comcast was absolutely no help to me. Oh, the new card is a Linksys NC100 Fast Ethernet Adapter. Everything is set to configure automatically. I have no firewall set up at this moment. I also tried different & new ethernet cables with no success. Whether I use the hub or not I lose my connection every few minutes on the computer only. I was able to sit and play Socom 2 last night for over an hour and never had a problem. Does anyone have any advice? Thanks!