Shoutbox

Yes, as long as you can access individual fines from your backup you should be able to access the registry via the windows 7 registry editor. I'm writing these steps from Win XP, I'm hoping the registry editor hasn't changed much/at all.

Open the windows registry editor (regedit in the search box on start menu)
Before doing anything in the registry, make a backup. Right-click My Computer at the top of the list on the left, and select export. save 'backup.reg' to the desktop or somewhere else convenient.
Navigate to the folder HKEY_CURRENT_USER
Go to File > Load Hive
the file you want to locate is ntuser.dat located in the user folder (XP: X:\documents and settings\user\ ; Vista: X:\users\user\ )
It will ask for a key name next, fill in something random (foobar works well)
Within the loaded hive, navigate to Software\Patchou\Messenger Plus! Live
Right-click this folder, and export it somewhere convenient
Highlight your created key again, and go to File > Unload Hive

Open your saved file for your Plus settings from the registry editor in a text editor, and do NOT double click the file yet to open it, you want to EDIT it first.
Do a search and replace in this file, and replace all instances of "foobar/" with nothing.
Save the file.
NOW you can double-click and merge the file with the registry. This should restore all your Messenger Plus settings back to the way you had it before.


EDIT: just noticed I already wrote nearly the exact same thing in the link from Andrey's post