Get a new hard drive and install 10 using the "I dont have a key option" once online you can use the 7 COA key to Activate 10.  You cant do this during install but you can after getting online.  All the Drivers for 790 are contained in a single CAB file.  You download the cab and move to my documents folder.  Then extract the cab contents using 7zip in that folder.  Any yellow ! in device manager are fixed by saying update driver from my computer instead of the internet. [URL] [URL]   Virtualization wont work because you require separate license to run 7 under 10. You do need a separate license, for Hyper V VM since those separate VMs are basically separate computers. Performance will be an issue with virtual machine.   [URL] [URL]  
Hi Gang I'm an older experienced Desktop user (with a new DELL Forum ID). I'm sure others have asked this question. Is it worth the effort to format an older Optiplex 790 Full Sized Desktop with a fresh install of Windows 7 Pro? Or have the required security updates been permanently discontinued? Reason I ask is that I have many older applications that install and run fine in using 'compatibility mode' within W7 Pro. OR Should I shop around for a newer faster Optiplex and make a switch to W10? I'm not sure these programs can still be installed and run within Windows 10 Pro? Thank You
Windows 7 Pro Security Updates?