currently I have ubuntu "installed on windows" and I was thinking about formatting and installing windows 8, but I want to keep my ubuntu OS. So my question was what could be done so I don't lose the information while I format (I don't have the HDD partitioned for each OS). Thanks in advance!
In a Wubi install the Ubuntu system is just stored on Virtual Disks, which are just a couple of files from the Windows point of view.
So just copy these files to an USB drive or some external storage medium.
Now, format your disk, install Windows 8.
Now, using Wubi install the same version of Ubuntu you had before, make sure to follow the exact same steps as before while doing the Wubi install.
After the installation, you should just be able to swap the newly created Virtual disks with the Old Ones, and you should be able to have your system back.
If swapping with the old disks is not possible, you can still use the old disks for recovering data.
Áfter poking around for a while I found this guide: (I had completetely forgotten this is called wubi, that's why I wasn't finding what I needed) https://help.ubuntu.com/community/MigrateWubi
Well heres what I do.
(do you have a second drive)?
Unplug Ubuntu Drive. Install windows on second drive.
Plug Ubuntu drive back in -> Boot Ubuntu.