I did not expect to miss Windows when I changed it to Debian here. Now I need to get the installation-media back. By which tool can I get the installation media back in Unix?
I use Debian.
You may wish to have a look at this video published by amzertech:
In which he explains in a simple way how to recover partitions with testdisk after you have deleted'em.
I have experienced this in the past and I fully recovered the partitions (bootable indeed) but I experience a mass loss of data because of I didn't stop working with my hard disk drive, thus harming my files.
First of all I suggest you to keep your hard disk drive off until you find a good solution that fits your needs and calm down. Remember that you can yet re-install Windows if you wish by using the proper installation CD/DVD.
Next, download a live cd of your favorite linux flavor and make a live usb with persistence in order to install testdisk, after installing it PLEASE!!! Please read the instructions.
You may be in the need to delete your current partitions in order to recover the previous. Tranquil, it is safe and provides good chances to bring back the previous partitions.
If you wish to run a bulk data recover in your hard disk drive follow the suggestions of other users in your previous question and use a forensics software to bring the data back. foremost comes to my mind, the same as photorec (this last is a cousin of testidk).
Please inform how are you managing your issue and...