Is there a way to find out when was the last time, the VM was rebooted ? I am looking from vCOPS and VCM.
you mean, a VM which was being monitored?
if it has vmware tools, you can look for the "...tools started..." event in the Events tab for this VM:
Also we keep a metric on uptime in seconds....Current time - up time = Last time rebooted.
The Metric Uptime is reset when you Power off then on the VM.
Could you please tell the location to see that metric ?
It is under System. There is a few metric's : OS Uptime and Uptime of the VM.