Doreen, my PSE software doesn't show in order history either. That's because I didn't buy it directly from Adobe which might explain why yours is missing too. Always treat purchased installers and serial numbers as though they were cash. If you can't find them your only other option will be to purchase the latest version which can be downloaded as a 30 Day Free Trial
Doreen, you could try to contact Adobe support and see if they can share the download link for you. Otherwise, the only other option would be to get the file from a friend or another forum user and then register it with your own personal serial number.