To debrand a phone its quite simple. All you need to do is flash the phone, this tutorial will show you:
XS++ 3.1 Guide-Flashing,Customizing,Recovering - Top Sony Forums
It will show you how to flash the phone but you will still need the files.
Firstly you need to find the language:
Top Sony - Languages Description
since you want your norwegian
And then go into download area, choose firmwire and then W610i:
Downloads - W610 - Top Sony Forums
and then choose the files you want to download.
BTW to download from this website you'll need to read:How to get access to Download Area? - Top Sony Forums