Ever wanted to find out your PC’s operating system installation date? Here is a quick and easy way to find out the date and time at which your PC operating system installed(or last upgraded).
Open the command prompt(start-> run -> type cmd-> hit enter) and run the following command
systeminfo | find /i "install date"
In couple of seconds you will see the installation date
Check the above screenshot of the command output on my Windows XP PC. It’s showing installation date with the precession of seconds.
hat tip from venkat