You can determine the operating system of your device by checking the About window.
Checking the About window
On the mobile device, click the Start menu and select Settings.
Click the System tab.
Click the About icon.
Click the Version tab if it is not already selected.
Check the version information (the Microsoft flag logo in the upper left corner of the Start menu indicates the version visually):
Windows Mobile 2003 – the text states Microsoft Pocket PC and Version 4.20 (the Microsoft flag logo is outlined in white).
Windows Mobile 2003 Second Edition – the text states Windows Mobile 2003 Second Edition and Version 4.21 (the Microsoft flag logo is not outlined in white).
Windows Mobile 5.0 – the text states Microsoft Windows Mobile Version 5.0 (the Microsoft flag logo is not outlined in white, and the OK button in the upper right corner is square in shape).
