Also Read :- How to Change Windows Installation Date and Time Using Registry Editor. Getting Windows Installation Date and Time with Command Prompt : Step 1 :- Open Command Prompt, you can use Start button to open it or you can also open it by Run Dialog Box. To open Command prompt using Run Dialog Box Press Windows+R button. Step 2 :- Now type CMD in it and hit Enter. Step 3 :- Now type the given Below Code in the Command Prompt Windows. Wait for few minutes, and after that the above Code will Display all the System info Related with the OS. For Install Date and time Scroll Up to the 10th line, there you will find the Date and Time at which you have installed Windows. You Might also Like – How to Change Windows Installation Date and Time Using Registry Editor.