WordPress reset itself for the third time

Hello,

For the third time now, it appears that my WordPress has reset itself. (2 times a couple of months ago and than I reinstalled it with all the configuration work as a consequence.
when I type in my webaddress: http://www.gerriedillen.be, I become the install.php page from WordPress.
It has been running for a couple of months now without any problem, and than suddenly…
All my files and photos are still at the server, I have checked the config and install files but I don’t see anything wrong.
Problem is that, when I install wordpress again, I have to retrieve my posts, simpleviewer plugin, and reconfigurate it.
I hope I inform you enough mentioning that I use WordPress 2.3 and the only (active) plugin is simpleviewer.

thanks in advance for your reply!

Best regards,

Gerrie