Constantly losing my connection only on 1 of my computers?

I have a home network with 4 PC's hardwired to a router and 8 WiFi connections. My setup is Cox Cablemodem-->Netgear Wireless Router-->DLink 8 Port Router. The computer that has been recently having issues is one of 4 PCs directly connected to the 8 Port Router. The strange thing is that if I simply connect another computer to this same ethernet cable it does not have the issue.

The issue is basically that I lose my internet connection, the only way to revive it is to do an ipconfig release/renew, and it comes back but only for about 2-3mins and I have to do it again. I have run Kaspersky Internet Security and all looks clean from a virus/malware point of view.

Cox is telling me to call my computer manufacturer (HP) because obviously the modem is working. Any idea how to begin troubleshooting this? I'm fairly certain it's something specifically with this PC but kind of lost where to begin looking... Thanks!

Dont waste your time contacting HP. Its probably software related which HP wouldnt cover anyway... Assuming your computer is clean, heres a couple of things you can try:
Reset the TCP/IP stack: Open a command prompt as Administrator and type or paste "netsh int ip reset". Reboot.
Disable IPv6: Right click on your network adapter icon for your LAN connection. Go into Properties and uncheck "Internet Protocol version 6 (TCP/IPv6)". Reboot.
One more thing, in case you havent done this already, reconnect the other pc to the 8 port (router or switch??) and double check to make sure none of the others are dropping connection and maintain it for a decent period of time.

Ok, I've done all of the above and it appears that the disabling of the IPv6 did the trick. Two questions...

- Any idea why this would only recently have become an issue?
- I'm thinking of re-enabling it just to confirm this is in fact what was causing the issue but hesitant!