I was recently contacted by a client in Llanberis who had accidentally closed an unsaved excel spreadsheet which contained a whole morning’s work. He had lost it all and was looking for a way to get it back. Unfortunately this is not possible (a fuller explanation is below) but I’d like to share a trick to prevent this from happening to you. Most likely, when you want to open a program you do so from its desktop icon or start menu entry. With data containing programs such as Excel and Word, do this: right click on the desktop -> New -> then select Microsoft Excel Worksheet (or whichever file type you want). Now, on the desktop you’ll have an empty file which you can double-click to open. This file can then run the auto-save feature should you forget to save manually. Then, should the worst happen, there will be a temporary file which can be recovered when you re-open Excel from the File -> Recent -> Recover Unsaved Workbooks button. However, none of this is a replacement for getting into the habit of pressing Ctrl-S every few minutes.
Leo Notenboom points out that Excel (and others) create a temporary file when they start which is deleted when the program is closed. The data would exist on disk, therefore and so could be amenable to data recovery. In the same vein, if RAM is limited, the file may be transferred to disk via the paging file. These files would be impossible to recover, however, if they were overwritten, which would be likely if the computer wasn’t shut down immediately. The upshot of it is, while technically possible, in the real-world it’s unlikely that anything could be saved.