I have this laptop (acer apire 5535-5018) that I re-installed the os system (windows vista home premium) but when I attempted to put in the product key that was on the back of the laptop it would not eccept it. I tried two more keys from different computers but it would not eccept either. So I re-booted and used a program to extract the product key from windows registry and that key worked to re-install windows vista. But when I wanted to activate, it would not allow me to activate, saying that it was an invalid key. Normally I get an option to dial a number and I can activate over the phone, but this time it would not give me that number, nor display the long set of numbers. It only gives me two options: buy an new product key online, or type a different product key. No key I type in is accepted. Has the product key activation been corrupted, and if so, how do I correct that problem?