DressageVid
If you purchased Premiere Elements 10 as an online download from Adobe, installation files should be available to you after you Sign In at Adobe under the My Orders at http://www.adobe.com.
You should have the serial number. But, your only hope is that you will find it after Adobe Sign In in your Adobe account under My Products at http://www.adobe.com. Premiere Elements 10 should be listed there and, when clicked on, should reveal your serial number.
Please let us know the outcome.
Thank you.
ATR