programs to get client information

Hi everyone,
I am trying to play around some thing that I can be used someday in my projects.
Is there a way to get the client's MAC address, computer name, cpu serial number, etc., that visited and logged in on my website? The goal of this is to know if the user is a hacker that infiltrated the user's account and doing something nasty in the site (e.g. updating member's profile).  I want to log this information in my database. Is there a good snooper program that I can use?
Request.ServerVariables don't work on me.

Thanks
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