windows 7 - Computer selects DNS server instead of obtaining it automatically

Ok sometime ago I changed my ip address to a static one because I was bored and I wanted to learn more about static ips. I am running windows xp. My laptop works find on the network that i set up a static ip address, but when i go to another network, the incorrect dns servers are being used. When I enter the option to get a dns server automatically, the internet connection works but only for a short time. After that the dns servers resets to the one i entered manually on a previous network.

I did this by going to Network Connection->Right Click Local Area Connection and go to properties->Select TCP/IP -> then click the Properties button.

At this point i am given the option to Obtain an ip address or obtain and address automatically. My question is how do I resolve this problem of the dns server reseting to the previous one.

Make sure there are no additional DNS servers in the advanced section of TCP/IP settings. You can see it the button at the bottom right corner of John T's Picture.

Try setting the DNS servers to also be obtained automatically:

You are likely viewing cached pages on other networks which is why it appears to work for a few seconds. If you have internal DNS servers specified, then you migrate to another network with DNS servers that are addressed differently, you will not be able to access your previous DNS servers unless they are external to the LAN.

You should first verify the settings of your network adapter's Properties / TCP/IP Properties / Advanced / DNS tab. It is possible that you have configured a DNS domain or forwards that correspond to your work network, so deleting this may fix the problem and return you to the purely automatic DHCP.

Switching between configurations may also confuse Windows Networking.

See this article :
How to use the Alternate Configuration feature for multiple network connectivity in Windows XP.

This article describes how to use the Alternate Configuration functionality to establish multiple-network connectivity. If you are a mobile computer user, you can use the Alternate Configuration functionality to maintain seamless operations on both office and home networks without having to manually reconfigure TCP/IP settings. This feature specifies that TCP/IP uses an alternative configuration if a DHCP server is not found.

With the Alternate Configuration, all you have to do is wait 30-60 seconds and when the machine doesn't find a DHCP server from the default settings, it will switch over to the Alternate Configuration.

However, if one or both of the locations is a domain, then you have a different problem and should probably look into a third party tool to make it easier.

One option is to set a public internet dns server instead of an internal dns server for your static dns entry. Options include Google (8.8.8.8/8.8.4.4), OpenDNS, and many others. The downside here is that you won't be able to use dns to resolve names on the local networks, only the public internet.

Mostly, though, you just shouldn't set static IPs on portable devices. Static IPs are for devices that are more, well, static... things like printers and servers. If you want a consistent IP on your internal network, the better way to accomplish that is to use a dhcp reservation.

Perhaps you have an antivirus program or malware that is changing those settings behind your back. Check services.msc for anything that might be managing your network or trying to protect you. Try temporarily disabling any "Network" protection on your antivirus, or seeing if you can go into Safe Mode with Networking and not experience your issue.

Failing that, I'd completely reset the network adapter by removing it from the Device Manager, and then letting it autodetect/reinstall on the next reboot.

EDIT: Just realized you were using XP. Don't know if XP has a "Safe Mode with Networking" option in its F8 menu...