Ever want to know how long your Windows PC has been running without reboot? Here’s how to find out without needing to install any extra software. Click Start, Run, then type CMD in the run box. Press Enter and a command prompt window will appear.(black box with white text if you are unfamiliar with it). Type “systeminfo” without the quotes and press enter.

Scroll the window back up and you will see a line with your system uptime.