vB3.7 crashed (db partially deleted) possible causes?

[flup]

Hi all,

my forum crashed yesterday/today. At first I couldn't see what caused it, there was a blank database error, no mails where being send. But after logging in to PHPMyAdmin I noticed almost the complete database having disappeard.

Some table started with the letter 'A' remained, all others where gone (15 tables were left).

I have absolutely no clue what happend and how, as far as I knew this vB version was save enough to run (never thought of upgrading because of the state the forum was in (custom template, custom mods, etc)).

Hopefully any of you can help me to find the cause to make sure this doesn't happens in the future again. Unfortunately, there also hasn't been made any backups since last january or december.

Any help/input/thoughts are appreciated.

Thanks.

--------------- Added [DATE]1306155065[/DATE] at [TIME]1306155065[/TIME] ---------------

By the way the exact version is unknown. The index.php says 3.5.4 but I'm pretty sure there was a 3.7.x (I believe .4) running.

[Fordies]

your host might have a more recent backup?..