Here’s a quick and easy way of checking how long a Windows server or workstation has been up, via the command line. It pipes the results of Net Statistics Workstation into find. Run the following from a command prompt:
net statistics workstation | find /i "statistics since"
The results will look like
Table of Contents
Statistics since MM/DD/YYYY HH:MM PM
Which shows the machine has been up since 02:45 pm on September 9th, 2017.