Don't try to move it yet. Just oil it (oil all the places the manual says to oil) and let it sit for a day and then try to move it. If it doesn't move, oil it again and wait again. The problem could be behind the face plate or somewhere else, so oil everything that moves. If you need a manual, you can download it free from ismacs.com or singerco.com. The oiling spots are in the manual. You can use heat to speed up the process by putting the machine in a hot car for a while. I understand a hair dryer will work too, but I'm not sure what you blast with the hair dryer.
Any sewing machine oil will do. You can use Vaseline for the "lube" stuff, if you mean sewing machine grease or what they called lubricant for the gears and the motor if you have a 201-2.
201s are like all those old machines, virtually indestructible. It's something stuck in the bobbin area, some old sticky grease in the "innards" or something like that. They will almost always move with some detective work, oil and patience. I have a couple of 201-2's. They are wonderful machines and worth the effort. It's one of two machines that are often touted as the "best machine Singer ever built".
bkay