In my organization, there are many user accounts whose users were laid off. Unfortunately, there is no way I can get the username of them from Human Resource. The thing comes to my mind is to check each users last logon attributes and disable the users that were logged in long time ago. But, I have over 1000 users. It takes forever to do so. Is there any command or third party that I can use? Honestly, I am newbie. So, I am not really familiar with cmd or PowerShell jargon.
if you are using Windows Server 2012, you can do certain search using Active Directory Administration Center.
Otherwise, you can use third parties which I have tested before: Borna AD manager, AD manager plus and OLDCMP all satisfy your need.