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Windows starts a high definition counter each time it boots, and this counter will return the milliseconds the system runs:
$millisecondsUptime = [Environment]::TickCount "I am up for $millisecondsUptime milliseconds!"
Since you will hardly be interested in the milliseconds, use New-Timespan to turn the milliseconds (or any other time interval for that matter) into a meaningful unit:
$millisecondsUptime = [Environment]::TickCount "I am up for $millisecondsUptime milliseconds!" $timespan = New-TimeSpan -Seconds ($millisecondsUptime/1000) $timespan
So now, you can use the timespan object in $timespan to report the uptime in any unit you want:
$millisecondsUptime = [Environment]::TickCount "I am up for $millisecondsUptime milliseconds!" $timespan = New-TimeSpan -Seconds ($millisecondsUptime/1000) $hours = $timespan.TotalHours "System is up for {0:n0} hours now." -f $hours
As a special treat, New-Timespan cannot take milliseconds directly, so the script had to divide the milliseconds by 1000, introducing a small inaccuracy.
To turn milliseconds in a timespan object without truncating anything, try this:
$timespan = [Timespan]::FromMilliseconds($millisecondsUptime)
It won't make a difference in this example, but can be useful elsewhere. For example, you also have a FromTicks() method available that can turn ticks (the smallest unit of time intervals on Windows systems) into intervals.
