I'm sure the gurus know how to do this but it is a daunting task for normal users. So, it would be great if one of the many gurus here could provide step by step instructions for the rest of us to go from an existing 8.1 oem factory installation to a dual boot 8.1 and 10. I've done some research and assume the steps would include 1. Discovering the existing factory installed W8.1 serial number 2. Image backup of the w8.1 (and create an install iso?? How? ) 3. Installing the free w10 update that part is relatively easy, but the following steps need how to advice: 4. Discover the W10 serial number 5. Create an install DVD for w10. *How? 6. Do what is necessary to get a dual boot. Maybe EasyBCD *But preferably a free tool 7. Somehow reinstall the backed up W8.1 into the dual boot system 8. Use the W10 DVD to add w10 as a dual boot. **In partitioning for the 2 Windows systems, how large partitions for each? **Can they share a data partition? "Step by step" instructions by the experts would be so-o helpful to us newbies and make the transition much easier. Thank you!