If you still have your old computer with Studio installed on it, you can just make a copy of your pixie file from your old computer and install it into your new computer and you should have no problems on the installation process.
I made a video way back on how to install Studio 12 without a previous version and seems it can also apply to your problem you have. If you want to see the tutorial video so you can have more or less an idea on how to install Studio 15 upgrade into your computer. You may skip some of the steps in the video if desired.