Control Panel > Network and Internet > Network Connections.
Right click on the network connection you want to change and go to
Properties, Double click on
Internet Protocol Version 4 (TCP /IPv4) and then click the
DNS Tab look for the various options and change to suit.
If you do not see any settings or anything obvious, this is most likely being set by your actual DNS server and you will have to change it there.
Lastly, you can also see if it is hard coded in the computer name. Open
System Settings (easiest way is by pressing Windows Flag+Pause/Break, click
Advanced system settings on the left and then go to the
Computer Name Tab, and make sure that it isn't set to computer.local, you can check/change it here - click the
Change Button, then the