Cannot log into existing installation

[Connie]

Saint,

1)
the user files are all stored in the folder /data/users
make a backup of the files there then follow the instructions which Chris gave

2)
you want to know if you can login as admin, why not try it? It will take only few time

3)
the best way in my opinion is to use user files from a backup
GetSimple offers complete backups and in those zipfiles you find the folder /data/users
I hope you have done such a backup, haven't you?

So delete all user files in that folder on your server and copy your "backed up" userfile to /data/users on the server

that's what I did when I forgot passwords etc.