This is just an alternate
idea to what AlbertP has posted. His idea is essentially very good.
*First, it does not surprise me that schools dont support linux. It seems that as long as Windows is around, things should be just fine. I know, it's sad, isn't it?
Secondly, back up Nadia to an external HD or CD. The reason for backing up is that when you install Windows 8, it is going to completely overwrite GRUB/MBR such that you won't be able to access/login to Nadia any longer. This is what is really upsetting about Windows.
*Thirdly, if you do intend on getting rid of Ubuntu, then you can install onto the former Ubuntu partition. If that becomes the case, go into Nadia and run gparted. Delete the Ubuntu partition and reformat it to become an NTFS partition and make absolutely sure you recall the partition size of that newly created NTFS partition size because when it comes to installing Windows 8. You want to make sure that Windows 8 recognizes the correct partition size. Not potentially
the incorrect partition size that Nadia is located on.
Run the CD for Windows 8 and ensure that Windows 8 recognizes/see's the newly created NTFS partition size. Install onto that partition.
The next thing you need to do is to install a Graphical Boot Manager. GAG is open source, recognizes Linux, Windows, and a host of other operating systems. I have used it before and it works fine.
GAG is here: http://gag.sourceforge.net/download.html
. You could use that one or one of your own choosing.
Install the free program onto CD and run set up for GAG. Use it to boot into Nadia and Windows 8. Make sure that you know which sector of the hard drive Nadia is installed on.
If all else fails even after GAG install and you still have Nadia backed up (hopefully you will be wise to do this), re-install Nadia and then back up Nadia from your back up source. Edit Grub as well so that it sees/recognizes the Windows partition. Grub should be working again along with Grub seeing your Windows 8 partition.
Finally, if the above idea is not suitable for you, you might want to Google "how to prevent windows from overwriting grub