Welcome to the Magix user to user forums. You will see I have moved your post to the Video products area of the forum since your question is about Video Saver, now called Rescue Your Videotapes/
I'm very sorry to hear about the death of your husband and the problems this has created for you with regard to changing the registration of your software.
In these circumstances the only thing you can do, I think, is to email infoservice@magix.net with full details of your husband's email address and the product you have, explain that he has passed away and his email is ended and that you want to transfer the registration of the software to yourself. Then you will also need to ask that they send you the serial number for the product.
I hope my suggestion will help you to resolve this situation.