I put in 2 weeks notice and had a new job
called my new employer after my last day
and was told I couldn't work their till my old companies owner said it was OK
My old company purchases equipment from them and has threatened to stop doing business with them
now i dont have a job!!!!!
what can I do???????

Other than start looking for another new job, one that isn't affiliated with the old one would be smart, not much.

It may be a long shot, but you may want to file for unemployment since you already had the new job. It's free.
You are also obviously suffering damages due to your prior employers actions. Were you that important to them, burn a bridge or are they just #$^#. I would talk to a couple lawyers about a civil suit to recover your damages and maybe their fees. It's free too.

I would guess you have received an offer letter (documented), which result in your resignation from your current employment. As long as it was documented, you can sue for breaching contract and do a search under “promissory estoppel”.

Call an attorney this a retaliatory firing in violation of Ca. state public policy and in violation of the implied covenant of good faith and fair dealing. It is a tort to induce the corporate employer to wrongfully discharge an employee, thereby intentionally interfering with his contractual relations and prospective economic advantage.Its a conspiracy breach as well,could also be seen as blackballing. In my view both company's are liable.
JoeC

Other than start looking for another new job, one that isn't affiliated with the old one would be smart, not much.
Who told you that ? That sounds like a stock H.R response.
JoeC