First if you have duplicate IP addresses, you need to be sure you're using DHCP so that your router can assign unique addresses. Then when your system can't find the PATH or IPCONFIG commands, that suggests a virus or corrupt system files, so I'd boot to Safe Mode and do a full system scan with the antivirus program. Then I'd go to an elevated command prompt and do SFC /Scannow to check for corrupt system files.
Good luck.
So tonight my mom tries to get onto the internet on her old desktop and she can't. she calls me over, since I'm the tech savvy person of the family, and there is a warning message saying that there is an IP address conflict with another system connected to the network. I went online to fix the issue (for windows xp sp3) and followed instructions from forums saying to go to command prompt and to type ipconfig/renewal. I did just that, but all i got was this message saying that ipconfig is not recognized as an internal or external command, operable program or batch file. back to the forums. they say to type the path command. guess what... a message that says NO PATH!!! I can't find anything online about the no path message, and this stuff is out of my league. WHAT IS THE ISSUE?!?! PLEASE HELP!

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic