H1B based on approved I-140

[sury77]

Hi,

Here is my situation:

I am employed by a company "A" and cleared the labour and I-140.
I have completed 6 years of my H1B and now i got extension of H1B for 3 years based on my approved I-140.

Now i want to work of another company "B"

1. Can the company "B" file H1 for me, based on my current visa status.
2. I want to process Green card through company "B".
3. What happens if i don't get my labour cleared with the visa period?

Thanks in Advance ! !