However, for all of your benefit, to play games on the Dr. PC Jr., you have to convert them from an iNES ROM (QND is the best program for that), and copy it to a high density floppy disk, and make sure the name of the ROM begins with "FC". The PCJR needs that to be able to play it. So, you can fill a disk with games like "FC1001", "FCEBZERO.PCJ", "FCMARIO", etc.
Some games might not work, but a couple have worked for me already, and I am happy.