How to Recover an Overwritten Backup From iTunes for Windowsby TS Jordan
Accidental overwriting of a file is probably one of the top five computer-related errors. Fortunately, there is a quick and easy method for turning back time on a Windows-based computer through the use of the System Restore utility. This will reverse the clock, making it as though you had not yet overwritten your important iTunes backup file.
Open the "Start" menu, click on the "All Programs" list, open the "Accessories" folder and open the "System Tools" folder.
Click on the "System Restore" program and select the option to "Restore this computer."
Choose a restore date that is before the time the iTunes backup was overwritten.
Click the "Next" button to begin the automated restoration process.