If you don’t turn off your computer at night and leave it on for days, at times, you might want to know for how long your PC is running. The system uptime information can be helpful to troubleshoot various issues as well. In Vista, Windows 7, and Windows 8, we can check the system uptime via Command Prompt or Task Manager. To check the uptime via Command Prompt, open Command Prompt, type systeminfo and then press enter key. Users who aren’t comfortable with the Command Prompt can open the Task Manager by pressing Ctrl + Shift +Esc hotkey and then switch to the Performance tab to view system uptime information. If you check the system uptime very often and are looking for a way to quickly view system uptime info, you should check out Uptime app. Uptime is a handy app for Windows 8 to view system uptime with a simple tap or click. It even displays the uptime on the Start screen with the help of live tile. Visit the Store, search for System Uptime (see how to search Windows Store), and install the app. On the first time, you will see “Let Uptime run in the background?” message. Click or tap Allow button to continue. You can also configure the Uptime to display system uptime on your lock screen. Open PC settings to choose Uptime app to display detailed info on the lock screen (check customize lock screen guide for more info). Please note that Uptime app will display the time since last system restart if you have Hybrid boot (fast system startup) feature in Windows 8. If you want to see the time since last shutdown, you need to disable the Hybrid boot. Check out our how to enable/disable fast startup (Hybrid boot) feature in Windows 8 guide to turn off or on the feature.