Invalid Product Key issue with Windows 8.1
I am having HP Pavilion 15 with Windows 8 pre-installed.
It was working fine, but whenever I tried to install updates it use to fail. I have recently got a suggestion and based on that I have disabled audio and video drivers and tried installing updates. After that the windows updates were installed successfully. Recently, I have also updated it to Windows 8.1. It is now asking for the Windows product key. When I have entered the correct product key from the CD I have, it is not accepting that. I don't know what I have to do now.
Please advise me what can I do? Thanks in advance for any help.