I have one of these as well. Yes you can put XP, 7 or a full linux like Ubuntu on it. Lots of older posts on the net.

http://forum.ultrabooknews.com/forumdisplay.php?333-Benq-S6

One of the better resources on it although there are others.

The main problem is the internal memory is 2gb, this device could come from the factory with windows, but that version had a 8gb internal memory.

If you put windows on it, it will have to be cut down some with a program like N-lite or V-lite. I haven't done mine yet. Still rocking Midinux on it. I am looking to see if I can get some packages to load on it to add programs. If I can do that I will leave it on there as I have other mini pc's running windows already.

(my first post here and just happen to run across your question)