Ok tested on 12.04, 12.10 and 13.04, is rather easy and I will add more info as I do more tests. Since we are talking Unity, do no expect right now for the launcher to go down like in windows (Bottom part of the screen). At least for now. The rest will actually change. So here are the steps:
Visit THIS SITE and download the latest theme version from there. It is called Win2-7 Remix. Extract the content of this to any folder. You will need to copy this later on. It should create a folder called win2-7 with everything inside of it including a sub-folder called unity.
Open Nautilus and go to your HOME folder. Once there press CTRL+H so you can see all hidden files.
Create a folder called .themes and copy inside of it the win2-7 folder you extracted earlier on
Install the Gnome Tweak Tool either from the Software Center, Synaptic or by clicking HERE
Open DASH and type "Tweak", you should see something like the following:
Open the Gnome Tweak Tool and select the Theme category.
Change the Current Theme and GTK+ Theme to Win2-7
Now everything should look like this:
The icons can be found HERE. You would need to extract the file and copy the content to
/usr/share/icons. It should look like
/usr/share/icons/win2-7_icons after you copy it. Now in the Gnome Tweak Tool, on the theme category, change the Icon option accordingly. I put this option as last since it looks horrible on 12.10 and 13.04 but on 12.04 it looked good for a couple of seconds.
WARNING - Since this is not official, you might get video corruption on the panel or the desktop, it might also stop working for a couple of seconds, feel slower, etc.. To go back, simply open the Gnome Tweak Tool and change the theme back. Or right click the desktop, select properties and change the theme from there.