Can't get computer to receive

Have set up many computer over the years to share a connection without issue and I've got a head scratcher now.

Cable connection (road runner) using a switch and both computers running XP home SP2. Computer A was already in use, computer B (a Dell) is being added to the connection.

Computer A works fine with a direct connection and through the switch.

Computer B was restored to it's original state after initial attempts to get it online (previously had a dial-up connection) due to excessive malware. Initially after the restore the computer still would not detect the connection (hooked directly to the cable modem) so thinking the onboard ethernet was defective I put in a known working ethernet card and still got the same results.

Computer B does not yet have a firewall or AV. Came preinstalled with a McAfee Suite trial (expired approx 2 years ago) that was uninstalled so we could download AVG & ZA when we can get online. Also completely disabled the windows firewall on the of chance there was some strange anomaly going on there.

Computer B was not able to obtain the IP (static) and I even tried using *shudder* the road runner install disc but I get an error message about no connection. I manually entered the IP, subnet mask, default gateway, DHCP server etc. and I then appear to have an active, working connection. I ran the connection repair tool and get a message saying windows can find nothing wrong with the connection now but it still doesn't work both ways. Checking the status of the connection shows oodles of packets being sent but a big fat 0 for packets received.

I find it puzzling that windows didn't even auto detect the connection like it does with any other cable or DSL connection...have never run into something like this before.

I have tried swapping the newly purchased cables between computer A & B and have hooked computer A up every way I have tried hooking up computer B and computer A ALWAYS works but computer B does not. Something in that computer is messed up or blocking incoming.....but what?

Any ideas?

 

Thanks guys for the replies. Sorry for the delay in responding...I've been on the go a great deal here in NY so my puter time has been hit and miss.

@ TxTazDad...have to say I'm at a loss on pinging computer A & B. Computer B cannot ping the modem, DHCP server or ISP. I have tried releasing the IP, flushing the DNS and renewing the IP via cmd prompt and although messages received were successful EXCEPT for the renewing of IP which it was unable to do, there was no change. This was done on Computer B. I have also reset the modem and the switch multiple times with both computers powered off and then powered on just computer B using a direct connection to the modem...no luck.

All ping test on Computer A are successful. Note: When I have both computers on at the same time IF I have them hooked to the switch I'm seeing a balloon message on Computer A as soon as Computer B is turned on that says "Windows System Error: There is an IP address conflict with another system on the network." This does not affect the connectivity on Computer A and the message does not show up on computer B until I open the browser.

Should I try flushing the DNS and renewing the IP on computer A?

@ TimW...both computers use IE as default browsers and are set to never dial a connection. Under LAN nothing is checked.

P.S.: Yeah it was! Sorry I missed seeing it in person this time but watching the feed on Computer A (LOL) and live TV at the same time I still got all choked up. Shazam! Simply an awesome sight to see!