H1B petition transfer unused un stamped from one to other employer

I am having H1B petition which has been filed from my previous company(employer 1). My petition has not been stamped from employer 1 .Petition was valid from 1 Oct 2015 to 30 Sep 2016. Currently i joined other employer 2. I have below queries.

1.Can employer 2 utilize my existing petition which was filed by employer 1.

2.Can employer 2 file new petition (without lottery process) in cap exemption quota based on unstamped unused old petition .

3.What are risk factors to do stamping in my case.

Appreciate your response.