You've lost your ESXi root password. Simple as that. You might not like it, but that's the world we're living in. It's your fault, you know it, the world will never be the same unless you quickly open up your browser and look for a solution. Take a deep breath, because that's gonna be tricky (...as tying your shoes).
Read more on my personal blog page:
Quickie #2: Reset ESXi Password - The Easy Method
