What were the exact problems caused by the malware? Did you correctly disinfect the HD by running a full scan of Malwarebytes
(in Safe Mode if necessary) then install the recommended Microsoft Security Essentials
to run another full scan?
If Windows 7 was unbootable did you follow the steps in Troubleshooting Windows 7 Failure to Boot
If you replaced the Windows 7 you say you fixed with a backup image then you are correct in assuming it should not carry over the infection if the image was old enough to not be harboring the infection - something which cannot be assumed for certain.
However to be safest it's best to wipe the HD with Diskpart Clean Command
first. Did you leave any partitions at all?