xiaobaitu, please help!

I just transferred H-1B to a new employer. My old employer called me back and told me my Labor certificate has been certified, which filed on Dec 2004. Is that the only way to keep the labor certificate is to go back work for my old employer? If so, do I have to transfer my H-1B visa back to the previous employer from my current one pr just use previous H-1B since it has not been expired. As well, can I concurrent file the I-140 and I-485 under EB-2. Thanks so much for your answer.