Good, goto Manage > Settings > Local Settings > Data Connection String. This will tell you where the database is located. Copy this file.
Then install SambaPOS onto the new computer making sure you tick
Compact SQL during installation.
Once installed, run SambaPOS and login to make sure all is working. Logout and Exit.
Then take the copy your existing database and copy to the same location on the new computer - the path may be different due to the username and OS.
Note: All data is transferred, including sales and any other testing you have done.
Look at this
http://forum2.sambapos.org/index.php/topic,60.msg177.html#msg177 to help with removing transactional data.
Good Luck.