Reinstalling will install the SQL CE engine, then you need to change the data connection string to create a SQL CE .sdf file. Since you have one on your desktop computer, copy that over and point to that.
You will need to re-enter you products and settings - no way around this. As stated TX is only for evaluating SambaPOS, it's not meant for production or serious testing.
The first time you create your menus, it will use the product name. If you change the product name after that, the menu will not change, but the two are still linked.