For physical retail copies, the serial number is typically printed on a sticker on the back of the CD sleeve or inside the box manual.
Even with a valid code, users often encounter errors like "Invalid Serial Number" during reinstallation. This is frequently caused by: JustAnswer Ulead Video Studio 11 Activation Key & Serial Number Q&A Ulead Video Studio 11 Activation Code
If the software is still installed on an old computer, you can find the key in the Windows Registry under HKEY_LOCAL_MACHINE\SOFTWARE\Ulead Systems\Ulead VideoStudio\11.0\Installer\ . For physical retail copies, the serial number is