That's rather special.
- First of all, there is no such thing as "during a restore point". I agree something might have happened, but it isn't clear what and when.
- Filext.com doesn't know the extension fxa. That's what I meant with "special".
- One earlier discussion about fxa-files: http://forums.cnet.com/5208-6122_102-0.html?threadID=158622. Not sure if it has a happy end.
- Windows.old shouldn't be changed by anything. To be sure of that, make all files read-only next time?
- If you can't read them in any way, get the original from your backup. No backup? Some people don't, indeed; they are likely to lose something some time.
Kees
In Vista during a restore point FXA Files were created in a windows.old folder. All my Media files were converted to fxa and now I cannot open them. The original folder is now empty. There are no Restore points to go back to and Previous versions don't exist including shadowing. I am fustrated because I cannot get these fxa files to open in any program to view my pictures. Anyone can help would be a great appreciation.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic