Unable to start TeamCity

Hi

I was evaluating TeamCity 8.0 (build 27402) last week and it was working fine.

Tried to start it up again today and I get the following message....

TeamCity server startup error                        
"Found a TeamCity internal database when no system directory or an empty system directory is expected"

Does anyone know what I've done wrong?I was using the Internal Database, as I was just quickly evaluting Teamcity to see if it met our needs.

All I've done since I last used it was reboot my machine.

Any help appreciated.

Martin.