I have used both activation for my indie version on mac. Since my macs are currently gone from the begining of this year, how I could activate the windows version?
Each license is meant for use and installation on two machines and two machines only. In your case you’re needing to migrate from one (or two) decommissioned machines and re-install on one (or two) new ones. In cases of hardware migration you need to write us at support@unity3d.com for assistance.
Ok, how do I do this migration?
Because at home i dont have mac anymore and there are small chances to get to the other computer since i have my leg broken 
(not to mention i want to change that too, since my productivity on mac is gimped).
In cases of hardware migration you need to write us at support@unity3d.com for assistance.
Write us. Now. All help shall be dispatched there.
I see, i thought there is a way to do this on spot. Ty.
I wouldn’t overthink it.
As HiggyB said, just write to support and tell them what you need, along with the relevant info, such as your product serial number and which licensed install that you want to “decommission”.
The Unity folks were VERY responsive when I did the same thing, and now my old PowerBook license has been “decommissioned” and I’m already up an running with my licensed install of 2.5 for Windows.