If you enter the Serial number and nothing happens, it means you entered entirely wrong, or selected another product for activation.
If the Serial was entered at least *reasonably* correctly, you should see a message "Do you want to activate xxxx on this PC?" and then (if you reply YES, of course), it will go online to check if the Serial is *really* correct and can be activated, or return some kind of error which should be easy to understand.
If you are not seeing that message, it means you entered the Serial totally wrong, or entered something else instead of the serial number (like the Order number or the SKU number, many do such mistake) or selected something else for activation: even if you insert the correct Serial for a product, if you haven't selected *that* one for activation, it won't work either.
