Just recieved approval on I-140 but ....got laid off

[FA1969]

I have just recieved my I140 approval notice but I was laid off meanwhile.
I got a new job on a new H-1b. My new employer is willing to help with my GC sponsorship.
Could I use my labor cert to file a new I-140 given that the job duties, description, salary and location (city) are the same??
Or will I still need to start a new labor certification case but keep my priority date (Feb 2000)?

What is the relevance of PD anyways?

Regards and thanks in advance

 

[H1Blayoff]

FA1969,
  One of my friends was in the same boat as you. He filed his 485 on the basis of the new employer. Received RFE to update employer information. Got approved finally.
  What I would suggest is try hiring a good lawyer and make your case. The worst case is you would not get your GC and loose $$. But anyways, without filing for 485 , anyways you are loosing that benefit. So take my suggestion and try filing for it before its too late.