Have TV Questions? Ask a TV Technician
Hello, and sorry you're having problems. We are now connected on this website- which saves you money over having a Tech come to your home, and in many cases we can fix the problem you're having. In other cases, these things do require additional parts to fix. But I can help you with that as well.
Offhand, some monitors won't let you change the Input if it doesn't detect an Input signal... so you mentioned the DVD player- why haven't you tried plugging that in yet? Do you have it there- can you give it a shot?
Also, can you verify the model is indeed TM42 and not TME42?