Follow these steps to find unsaved documents that you were working on in Microsoft Office for Windows:

1. Launch the Office program in question (e.g. Word, PowerPoint, Excel)
2. Open the 'File' menu
3. Click 'Info'
4. Open the 'Manage Versions' drop-down menu (newer versions of Office use ‘Manage Document’ or ‘Manage Presentation’)
5. Select 'Recover Unsaved Documents'
6. There may be more than one file showing, open the files until you find the one you want

Alternatively, you can see all the unsaved files at once here: C:\Users\YOUR USER NAME\AppData\Local\Microsoft\Office\UnsavedFiles

There is no guarantee the missing file will be here.