Dear Dave,
Thank you very much sir for responding.
I am unable to reply on this thread and continuously trying to do the same but not working so I am editing my question to respond you this way.
Now about the fixes you mentioned I have checked task scheduler already and i am aware that there is no task running at all.
But as you suggested I will check my BIOS settings that it might have off setting. but sometimes when it shuts down i try to boot it again but while booting CPU stops again and don't let me boot my workstation but also sometimes when i try multiple times it may happen that in a try pc starts working again but it may power down soon or may be not.
So there is no thing that is coming in my mind that what could be causing this issue.
Thanks again for helping sir.