if I load a previous save game then load a more current one will it work?
Only one way to find out.

If it was me though I would make a manual backup of my save folder first.
for XP the folder is in the path:
C:\Documents and Settings\*your pc name*\Local Settings\Application Data\Divinity 2
You may need to allow "show hidden files and folders" in your tools/folder options to find it.