A likely problem is the fences in the paper tray that keep the paper aligned. Make sure the fences in each paper tray are snug against the paper.

Also make sure the fences are aligned correctly -- take the paper out of the tray, unlock the fences (using the lock button on the back fence) and push them as close together as you can. If they both touch or almost touch the gray metal plate in the middle of the tray, they are aligned correctly. If they don't, they are misaligned, and that is probably why your registration is off. If you have a screwdriver, you can fix the fences yourself, otherwise call your service technician.

Make sure the paper is in the right cassetts or you could have a problem whih the reigesation settings.