Need info about HD crash and rebuild

Hello,

I had a HD quit and have replaced it. I used my recover disc and have the unit working. I had
a couple copies of a backup and this replaced most of my files.

My question is I have a backup image made in Feb 2013. Can I use it and write over the system
info now on c drive, and not cause a lot of problems. I don't want to kill what I have installed or
rebuilt so far. From my understanding, this image has the OS and other data on it. This image
is 106 GBs in size.

I have Windows7 Home edition, and had changed it to Windows7 Professional. I can not find
my key to make the upgrade, so was thinking it may reinstall it if I use the image backup.

Running HP computer, 64 bit, 500 GBs HD, 6 GBs memory. My system before crash was using 218 GBs
of space on HD. HD is now using 106 GBs, with 347 GBs free.

Can any one advise.

Thanks for any help. :)