NoelDP said:
The 48-digit confirmation code is not necessarily the same every install - and certainly not the same, if yu change any of the essential hardware (NIC, CPU, Motherboard, first HD, Video, etc.
Yeah I know that, to activate via automated phone service, the hardware hash (also 48 digits) was generated by Windows, and I had to tell it to automat, and automat returned 48 activation ID. Since I did not change anything, it worked the next reinstall too. Well, I still hope it will return to normal, after some time without reinstall.

Reinstall of W7 itself is not that time consuming (USB flashdisk ---> Vertex 3), but settings and control panel, and programs I need to install and setup, and of course Windows updates. So it will make drive image with everything, drivers, settings, registry, installed software, all registrations and network settings and Windows Activation? Does it work with games too?
Well, it definitely looks like great idea. Thank you for your replies.