I recently changed my system drive (C:) and did a clean Windows (8) reinstall. When I reinstalled Starcraft 2 (which I hadn't been playing for quite a long while), the game asked me to create a new character and start a new campaign. Therefore, all my achievements, progress and saved games don't appear any more in the game.
From what I read, those informations are stored locally, in the "My Documents" folder. Both in my previous and current config, I have set Windows to store this folder on another drive (D:), so this folder hasn't been erased when I reinstalled Windows, and all my data form my previous SC2 install is still there: I can see the folder of my previous character (and it's 500MB worth of data), but for some reason the game ignores this folder and creates a new, empty profile.
I also have a backup of this folder somewhere else, so I tried uninstalling SC2 (with the option to erase local saved data), restoring this folder from the backup and reinstalling SC2, but it didn't change anything. When I log in, I still access my new, empty character.
How do I force the game to use my old character ?
(I also still have access to my entire old C: drive, if that helps.)
(Edit: I tried to ask this question on the battlenet forums (http://us.battle.net/sc2/en/forum/13438/), but it says I have a "trial account" and must upgrade to a full account in order to create a forum thread. I don't even know what this means...)
(Edit 2: problem solved. See my answer below.)
(Edit 3: see the accepted answer for the real explanation of the problem, though. ^^)