System image restore on empty external drive

No, thats not my problem to backup user files.

I want to know what I do in case of a complete disk failure.
Do I have to the buy the same disk (manufacturer, size, model) as my current
internal hard disk ?

It seems to me that the Microsoft restore has in its image backup information
about the disk from which it backups. But I only can assume this.

I tried to cheat the restore program by putting my external target disk 1st in the
boot sequence of the BIOs, but this did'nt work. So the proposal with the SATA
connections seems the only possibility to get my backuped running system on
a new empty disk.

An image can be restored to any internal disk that is the same size or larger than the original. But the BIOS must then find it as C. That's why you could not "fool" the BIOS. But if you want to restore to a smaller disk, then you need one of the other programs that were mentioned. Imaging is a pretty stupid bit copy/restore process with little logic involved.

This is exactly my problem. If the restore isn't possible to an external disk
how do I succeed that the BIOS finds an additional SSD drive as C:
and the restore doesn't go to my then second internal disk where my Windows 7
system is on the first partition ?

Does the restore always take the disk, that is on SATA1 ?

For you SSD you need a different approach anyhow - as I have described in my earlier post.