I was building a new budget gaming computer, and every computer needs an operating system. I'm not quite ready to jump on the Windows 10 band wagon, and Windows 8 leaves a lot to be desired, so Windows 7 was a no brainer for me. As usual, Amazon had the cheapest price and with Prime shipping too.Everything installed easily, and I didn't think much of it until a month later when Microsoft insisted I active my install. I went through the process of calling the number and typing in all the numbers into their appropriate boxes, but in the end it kept telling me my product key had been blocked by Microsoft and I would have to purchase a new key. I immediately called Amazon customer service and even though this was purchased through a third party and fulfilled by Amazon as well as past the 30 day return window the customer service rep refunded my money and provided a return shipping label.Yes I lost a little time messing around with the install trying to activate it, but in the end Amazon's customer service was as good as I hoped it would be. The error message is because Microsoft will not support, or supply ISO files, for OEM-licensed systems like yours. The best solution is to go back to the shop that serviced your computer and tell them to reinstall the proper licensed copy of Windows 7. If they refuse, you can download a ISO file for Windows 7 Home Premium by using the tool described below. You can create an installation DVD from the ISO file by using ImgBurn (http://www.imgburn.com/) or an installation USB flash drive (if your VAIO can boot from USB) by using Rufus (https://rufus.ie/). ImgBurn and Rufus are both free. Once installed, use the product key from the COA sticker on your VAIO to activate Windows. You can obtain a legitimate Windows 7 ISO file by using the download tool here:https://www.heidoc.net/joomla/technology-science/microsoft/67-microsoft-windows-and-office-iso-download-tool. If you are willing to use an ISO file from August 2018 (5.5 GB), you can download that immediately. However, if you want the original version, downloads are quite limited. Notes below from the Heidoc support forum. "The download database on the server will be reset on the first day of every month. We will then generate one link per hour on a first come first served basis, whatever is requested, until all licenses are used up.