If you serial is showing as invalid, then most likely the program is not able to access the Internet to complete activation.
If you are not able to activate the program with the supplied serial number after adding PC Booster to your firewall, please kindly complete the following steps to activate the program:-
We strongly recommend copying and pasting your serial key from your order receipt into the program. To do this go to your order receipt. Using your mouse, right click on the serial number, ensuring no extra spaces or blank spaces are copied. Please right click and press Copy or press CTRL and C on your keyboard to copy it to your clipboard. Please then go back to the program, click on Register now, and then Enter Product Key. In the space provided, please then right click with your mouse and paste the serial number. Or in the space provided, press CTRL and V on your keyboard to paste the contents from your clipboard into the registration area provided. Please then press Active Now to complete the registration steps.
If your question has still not been answered then please submit your query to us and we will contact you as soon as possible.