Hi, my name is ***** ***** I'll be happy to help you today!
Once upgraded to Windows 10, the system gives you 30 days to roll it back to the previous operating system. If you don't do it within that window, it deletes the files for the reinstall the free up space.
If you're within the proper window, you should be able to roll the system back by following these steps:
1. Click on the Start Button in the lower left corner
2. Click on the Settings icon in the lower left corner of the menu (looks like a gear)
3. Go to Update and Security and then click the Recovery option on the left.
If you're system can be rolled back, you'll see an option to go back to your previous version of Windows on the right-hand side. If the option is not there, then I'm afraid it has expired.
Just let me know if you have any other questions on this!
NOTE: If you have no further questions on this, please use the rating box at the top of the page to rate the answer at least 3 STARS/OK SERVICE or better to end our session for now. I will stand by until the answer has been rated.