In the single-user version, your Xpert-Timer database is stored locally as an Access database or SQLite database. The database can be found in your installation directory in the "Database" folder. On Windows 10 you find it in your documents folder. Xpert-Timer database is stored as xt.sqlite or xt.mdb.
The xperttimer.ini file stores your connection details and personal settings. Where your .ini file is located can be seen under the menu item "Help" in the Project Manager. Select the sub-item "Info about Xpert-Timer" and then the tab "System Info". There you will find more useful information.
If you work with a SQLite or Access database, Xpert-Timer automatically creates backups. By default, the path points to: C: \Documents and Settings\username\MyDocument \Backup XpertTimer
There you will find the data backups for your database. The file names include the date and time of the backup.
If you use an MS-SQL or MySQL database, you can simply reinstall the Xpert-Timer on your new system and connect to the corresponding database. To connect for the first time, press the Ctrl key while starting Xpert-Timer. This opens the database connection dialog, which lets you select the appropriate database.