Hello, I have a question: I want to purchase the avast internet security, but it seems that sooner or later I will also have to buy a new computer as this one is ready to collapse!Will I have to buy again another key for the new computer or it´s possible to continue using the same product to the new computer?
No need to buy a new key, you can use the old one. 
asyn
But, please, save the license file to a safe place (USB drive) in order to use it in the new computer.