Giveaway of the day,
I found what was the problem: I used the installer from the developer's site.
You should have told us that only the installer given here, will work with the given key and any eMail.

Laxative,

"I am inclined to the former."

And you would be wrong, at least some of the time.

The way the Windows file systems work, files & folders are stored in small pieces, & there's a sort of Table Of Contents that lists which pieces make up which files/folders, & where those pieces are stored physically. Nothing stored on a regular hard drive goes away, unless new data is written in its place -- when you delete a file/folder, delete a partition, quick format a partition/disk etc., you're just deleting part or all of that TOC. That's why they have disk wiping or erasing apps to clear the drive before you return or sell a PC, laptop etc. SSDs are another matter -- unlike a regular hard drive, you can't just write new data on top of old data, but have to clear the old data 1st. Since we, & Windows, & software are always writing & deleting files, that 2 step, clearing old data to write new, would slow SSDs down, so there's TRIM. It basically clears storage proactively, so if a location isn't listed in the TOC, it'll make sure there's nothing there, so writing to that location is faster.

Recovery apps scan a drive/partition making lists of every bit of stored data they find. Then they try to reassemble files/folders from that data. Apps like Erelive Data Recovery really do work -- the catch is that if a storage location has been cleared, or if something else has been written there, the old data is gone. After a quick format, & nothing else, you'd likely recover most everything -- after a system reinstall, lots of new data has been written on top of the old, so you couldn't recover everything, but you'd still very likely find stuff. If you want data to be gone forever, look into file wiping or erasing apps for conventional hard drives, special utilities, including from the manufacturer, for SSDs, or simply physically destroy the drive, which is what a lot of biz & gov agencies do.

mike,
1. "after a system reinstall, lots of new data has been written on top of the old, so you couldn't recover everything" — that speaks for itself.
2. after a quick format, there is a good chance of a lot being left, but I was thinking of a normal format, which is complete (and as they do not say ‘quick’ one is entitled to assume a normal format), which wipes out everything.
Since a high percentage of GAOTD offers refer to data recovery, one would look for something different here, and what is different includes the two I mentioned.

TK, I find your syntax a little difficult to follow but get the idea.
Still the idea of a format is that it wipes the entire disc clean to start again. Nothing will remain. There is I admit a ‘quick format’ which does not do this, but only a partial cleaning. That is why it is quick. If you simply format a drive it cleans up everything.
The eraser tools enable you to wipe out files etc. without wiping out the rest of the drive but a format wipes out all.

Min, in regard to checking registration status, the registration option disappears from the menu after registering. ;)

TK, very similar concerns in this recent offer https://www.giveawayoftheday.com/ifind-data-recovery/#comment-576117
It seems the Chinese market for data recovery products is flowering