I just purchased a new laptop and I want to decommission my old one. I have a back-up of my wallet.dat file copied to my new PC. What do I need to do to restore it to my Bitcoin (Windows) client? Please note, this is a wallet.dat file that is about 6 months old and I haven't loaded it in at least four months. I'm not sure if that makes a difference or not, contingent on the original version of the client that created the file.