Uniqely Identify a computer?

This might be a duplicate question but as you can see they didn't get the correct answer.

How to uniquely identify a computer?

Uniquely identify one computer

how would you remembers a computers regardless of ip, "browser" cookies, and browser itself. So It will recognize it once you use it from another browser, or ip address. Any ideas?

UPDATE

I found out that there is a possibility using flash cookies: it seems that it's shared across browsers and clearing the browser cookies does not remove it. my question now is how can I see my flash cookies and know if that is what facebook is doing?

• Ubiquitous availability (95 percent of visitors will probably have flash)
• You can store more data per cookie (up to 100 KB)
• Shared across browsers, so more likely to uniquely identify a machine
• Clearing the brow开发者_开发问答ser cookies does not remove the flash cookies. --Joeri Sebrechts

I suppose a flash cookie is a bit more cross browser and persists.

Facebook only remembers based on the cookie in your browser.

The proof to the pudding is if you login and then switch to a different browser, you are not logged in there.