How to retrieve files from the Windows.old folder
If you choose not to keep your files when you upgrade to Windows 8, your files will be temporarily saved to the Windows.old folder (unless you formatted your hard drive before installing). If you decide you want some or all of these files back, you can still retrieve them.
You can run a troubleshooter that will automatically retrieve your personal files from the Windows.old folder and copy them back to their original location. The troubleshooter will work on all languages but the text in the troubleshooter is only in English.
Swipe in from the right edge of the screen, tap Search (or if you're using a mouse, point to the upper-right corner of the screen, move the mouse pointer down, and then click Search), enter Computer in the search box, tap or click Apps, and then tap or click Computer.
Double-tap or double-click the drive that Windows is installed on (typically, the C: drive).
Double-tap or double-click the Windows.old folder.
Double-tap or double-click the Users folder.
Double-tap or double-click your user name.
Open the folders that contain the files you want to retrieve. For example, to retrieve files in the Documents library, double-click Documents.
Copy and paste the files that you want from each folder to a folder in Windows 8.
Repeat steps 5-7 for each user account on your computer.
When you're done, you might want to remove the Windows.old folder, to save space on your PC. For more info, see How do I remove the Windows.old folder?