DNS Server settings auto change

Clarifications

If you are getting IP information from the ISP's DHCP settings, you simple need to make sure that you do not have a hard coded IP address in your TCP/IP settings.

Where are you trying to change the IP address for DNS?

Download Malwarebytes Anti-Malware, install it and update it.

http://download.bleepingcomputer.com/malwarebytes/mbam-setup.exe

* Double-click mbam-setup.exe and follow the prompts to install the program.
* At the end, be sure a checkmark is placed next to Update Malwarebytes' Anti-Malware and Launch Malwarebytes' Anti-Malware, then click Finish.
* If an update is found, it will download and install the latest version.
* Once the program has loaded, select Perform Quick Scan, then click Scan.
* When the scan is complete, click OK, then Show Results to view the results.
* Be sure that everything is checked, and click Remove Selected.

I would keep scanning with it until it is clean by closing out and rebooting and running it again.

Just to be on the safe side when you finish do an online scan with Bitdefender. Or Google for an online scanner.

http://www.bitdefender.com/scan8/ie.html

If you can't access the internet to update MBAM try the instructions below to clear a pathe to the internet to be able to run MBAM.

From another PC download and install Spybot, update it and copy the the installed folders to a USB Stick.

Restart the PC in Safe Mode, navigate to the USB stick and run Spybot.

Download Spybot - Search & Destroy and install it. Update it. http://www.safer-networking.org/en/download/index.html