two separate Windows 7 operating systems

[Bones 1147]

I have a situation! My Computers hard drives both failed within a week of each other. I lost my files (D) drive first, literally caught on fire!! Then my C drive went. I found I had a back up on an external drive, but not before I started to do a complete rebuild of the operating system from a different Windows 7 Pro disk. I cannot find the older disk, which was Win 7 pro also. I used only the 64 bit option on both, and Installed service pack 1. My big problem is I do audio, Pro Tools, and video production, Sony Vegas, on this PC, and all the 3rd party plugins that I licensed 6 or 7 years ago will not install for some reason. The vendors cannot figure out why? So to the question. Is it possible to re-install a second bootable Windows 7 operating system in the same computer from the back up I found? And am I going to have issues, not having the old disk for serial numbers etc? I'm afraid to try to re-install the backup over the new system and loose what work I've managed to accomplish at this point This might be a goofy question. I know enough about computers to get me in trouble if you know what I mean?

 

[SIW2]

Is it possible to re-install a second bootable Windows 7 operating system in the same computer from the back up I found?

Yes, if the "backup" is an image and not damaged.

I'm afraid to try to re-install the backup over the new system and loose what work

No need to do that. You should be able to restore an image to a separate disk.

What kind of "backup" is it?