Can you clarify what you mean by the Desktop tries to take the iPad back to factory settings when you connect it?
The registration will have nothing to do with the restore hanging up, the worst it would do is block you from some apps because of your location, So can you tell me if you are connecting to a Mac or PC and can you tell me if you get an error when restoring the iPad?
Can you also tell me if you are connecting the iPad directly to the machine or if you are using a USB hub?
Can you tell me what version of windows is on the machine?
In that case can you click start then control Panel and then can you select the Add/Remove Hardware option then locate Apple Mobile Device Support and right click it then choose remove.
Once it is removed can you then open your My documents folder then open Music and open the iTunes folder.
From there can you right click on the iTunes music folder and choose copy then close the window and right click on an empty part of your desktop and choose Paste so that we have a copy of your iTunes library on the desktop.
Once that is done can you click Start then control panel and open Programs, Find iTunes in the list and give it a single click to highlight it then choose remove.
Once it is removed can you restart your computer then follow this link http://apple.com/itunes/download to download a fresh copy of iTunes to your desktop.
Once the program is downloaded can you install iTunes just like normal.
After it is finished can you then open iTunes and let me know if it will run properly and that all your music is listed.
If it is will you then connect your iPad and then follow the prompts and let me know if it will now install and then restore properly or if you get any errors.