HI,
I want to find out whether a hard disk of my computer was removed and taken out for some time.
Is there some kind of log inside the computer?
How to find it :
Where is it stored?

How many hard drives do you have in your system? Are you referring to the hard disk that your operating system is running from? Which operating system do you use? Can you be more specific about what you think happened in order for us to provide better help?

The basic answer is no. There is no log that would indicate whether a drive was removed from a system. Nothing is recorded by the system when its powered off.

What makes you think the drive might have been removed?

I've seen some older HP/Compaq desktop PC models that included a "case intrusion" alarm in the BIOS. It's certainly not a common feature, but if the system did have it, I know I've seen it in the BIOS.

This would not tell you if the hard drive was removed, only that someone had opened the case on a particular date and time and triggerred the case intrusion switch.

I've only seen servers come with detailed hardware monitoring and logging built into their firmware that tells you when items were added, removed, or modified.