Your Roxio serial number (or “product key”, or “CD-key”) has a maximum activation threshold for 20 installations. Each install will consume one activation count the moment you enter the serial number and hit the “Next” key. Eventually, after successive installations, you will end up using up all 20 activations granted to your serial number. After the threshold has been maximized your next install attempt will prompt the message “Key has been used too many times”.
To be able to use your serial number again you will need to contact Roxio technical support to have the serial number's activation threshold reset to zero.
On the unlikely event that the installer stub continues to prompt you with "key has been used too many times", you will need to perform a quick maintenance procedure on your system. To begin, close all programs, including your Roxio installer, and delete the Windows Temp files - Press Windows key + R on your keyboard to bring out the Run command dialog box, type in %temp% and click OK.
This should bring out the Windows Temp folder, shown below. Select everything in the folder by clicking the "Select All" and hit the Delete key.
If you get a "Folder access denied" or "Folder in Use" dialog box, that means some files inside the Temp folder are currently being used; so, simply press the Skip button to proceed.
If there are quite a number of files in use, you should be able to spare yourself from some tedious mouse-clicking by putting a check mark on the box beside "Do this for all current items."
After performing the steps above, reboot your computer, sign back in, and try installing again using your serial number. The serial number authentication routine should go through and check out this time and the installation will initiate.