Find last boot time

When did we last reboot this machine? What's the current uptime? How long since boot, since reboot, since last boot, since last reboot?

In powershell 2:

Get-WmiObject win32_operatingsystem | select csname, @{LABEL='LastBootUpTime';EXPRESSION={$_.ConverttoDateTime($_.lastbootuptime)}}

In Powershell 3+

Get-CimInstance -ClassName win32_operatingsystem | select csname, lastbootuptime

Source

• PowerTip: Get the Last Boot Time with PowerShell