Wireless Setting change, unexpectedly: DNS

Hello,

Every time I log on to my laptop, network is not automatically connecting. The issue is with the wireless connection / settings / TCP/IPv4 protocal. Its changing from "Obtain DNS server address automatically" and entering a DNS server address.

I have to go in and change it every time.

I've completed a full scan for malware, but no luck.

Anyone know what it could be? Or, anyway to either lock this down, or add a watch to see which application is changing it?

Many thanks
David