“Already Installed” – but there is no installation …

I uploaded the brand new wordpress 2.3 folder. Then, I created the ‘config-file‘. After that I get this message:

All right sparky! You’ve made it through this part of the installation. WordPress can now communicate with your database. If you are ready, time now to run the install!

When i click on “install”, I get the following message:

Already Installed

You appear to have already installed WordPress. To reinstall please clear your old database tables first.

There is no other blog installed. I had one, a year ago, but I deleted this one a month ago in removing all files from my host.

Please help me.