Swannie, I upgraded to a Pfaff Creative Sensation from a much older, simpler Pfaff and I do agree that there is a learning curve. Most things I have managed to work through with patience and practice. However, once when I was quite stuck I called Pfaff support. The woman I spoke to was very friendly and helpful, so you might think about that if you are getting error messages that you don't understand. When you get the 'check top thread' message, is the thread broken? If so, you might try lowering the thread tension, or changing thread brands, or changing the needle. If it's not broken, review the threading procedure in your user's manual.
Sorry that you are so frustrated with your new purchase. I hope you are able to work through the problems.