You can find the version of the Windows running on your computer by doing the following steps.
- Click on Start button
- Click on Run
- Type the command winver and press Enter. Now you will see a window like below.
The above window shows the following information about the Windows OS I have on my PC.
- The OS is Windows XP and the edition is Professional.
- The latest service pack installed is SP2.
- The exact build number is 2600.xpsp_sp2_qfe.080814-1242
This method works on all Windows OS releases – XP, Vista, Windows 7, Windows 2000, 2K3 and 2K8.