Is it possible to back up the whole datebase and program onto a USB drive. If so, which file do I actually back up, do I just back up everything listed under OpenLP in program files.
You shouldn't backup the Program Files folder as that just contains the program itself, which you'd need to reinstall from the setup exe.
What you do need to backup:
1) The OpenLP data folder. Find this at Tools > Open Data Folder. On win7 it's at C:\Users\<user>\AppData\Roaming\openlp\data
2) OpenLP settings. These are stored in the registry which you can't easily backup directly. But you can export them from within OpenLP: File > Export > Settings
3) Files in the media tab and video tab of the Media Manager are not copied to the OpenLP database. You'd need to backup them up from their orginal location.
4) Service files (*.osz) are also not stored in the database, and would need to be backed up from their orginal location.
Hope that helps.