Limiting liability in new company start up

Re: Limiting liability in new company start up

See Starting a business: http://www.ss.ca.gov/business/resources.htm for general background information

LLC or corp would work!

My question has to do with starting a new company. I currently personally own 2 companies. I am looking into a new business opportunity in which there would be an investor with no ownership expectation. My question is what type of company would i file for so that if something would happen to the new company nothing could happen to my already existing companies under any circumstance. Or is there such a thing.