If you want to use event viewer to find the booting time of your machine, then follow the tutorial below.
What is Event Viewer?
Since 1993, Window NT has Event Viewer in it. This centralised operating system component keeps track of all the events happened in the computer from the beginning. This let the administrators and normal users see the events occured. It keeps track of events from booting the machine to any problematic shutdown event, any settings change to any application installed and all other events. If you want to know whoever used your computer in your absence and whatever he has done from the Event Viewer. The Event Viewer has three log sources: System, Application and Security.
Only the Local Security Authority Subsystem Service (lsass.exe) can directly write to the Security log.
System and Application log sources are maintained by the Windows operating system and Windows applications respectively.
If you want to know the booting time of your machine form the Event Viewer, follow the instructions given below.
1. To open the Event Viewer type “event viewer” into the Windows Start Menu and press ENTER.
2. It will open Event Viewer and you will be able to see what is going on or went on in your computer.
3. Now navigate to Applications and Services -> Microsoft -> Windows -> Diagnostics-Performance in the left pane of the Event Viewer .
4. This folder houses a log called Operational. Double Click on this log to open it.
5. Click on the Filter Current Log which is on the right pane.
5. This will open a Filter Current Log box.
Tick the Warning box and specify an Event ID of 100 and Click OK.
6. It will now only bring up events which have an Event ID of 100.
7. To get the boot time double click on the Warning message to open it.
It will be displayed in milliseconds so to get it in seconds you should divide it by 1000.