XP Peer to Peer Dropping Connection

I have three computers - one dell precision 360 - one dell optiplex GX 520 - One IBM X 40 Laptop. I am trying to use the precision 360 as my main hardrive for data files. I have setup a workgroup with all three using the same workgroup name. I have a comcast cable modem, I keep losing connectivity with the dell precision 360. All computers are running through a router. Any ideas on how to correct would be greatly appreciated.

 

My first thought on this may be a failing network card.

 

Or a bad cable/connector ?

Switch it with some other computer to rule it out.

 

When the Dell 360 loses connectivity to the LAN, does it also lose Internet access? Might be a helpful clue.

 

I have had network cards checked, used another computer as server, and had the cable company test my router and perform any upgrades necessary. They also say my issue is not a connectivity issue. I appreciate each of your suggestions, but I am still scratching my head. Could a power surge issue be causing this?

 

Connectivity to your router/modem is not an issue here. The issue here is internal network which your cable company would not test/troubleshoot for you.

Have you done anything suggested so far ?

 

When you say you lost connectivity, what do you mean by that?

Get IP status for your computer:
Start-> Run-> Type in "CMD" the Enter if Windows Xp.
Start-> type in "CMD" in Start Search bar at far left bottom for Vista.
Type in "ipconfig /all "
Look at active IP Status. Look for following info...

Ethernet adapter Local Area Connection:
...
IP Address.........:192.168.1.5 or maybe 192.168.1.105 or something like this
Subnet Mask......:255.255.255.0
Default Gateway.:192.168.1.1 or something like this
DNS Servers.......:201.68.97.10
:201.68.78.102

Check this in the dell precision 360 and compare to known working when you have lost connection.

If the dell precision 360 has something different it might be worth assigning IP address and DNS servers in TCP/IP config.