You will almost certainly find it easier and simpler to start over. Unless the old non profit was for the same purpose and uses the same structure you will need to file new exemption applications (Form 1023) with the IRS. Unless you have been complying with the proper reporting and filing requirements, you will likely find your entity has been suspended in any event. Check the public records through the Secretary of State's office.
In general a tax exempt entity is not an "off the shelf" tool. They are normally organized as a California non profit corporation or by establishing a trust. Each type has specific operational rules and its form and structure is governed by it's exempt goals. While you can spend time and money doing the research to see what happened and trying to bring the old structure up to date, it is often much more cost effective to start anew. To find out, locate all your organizational documents, and check to see if the needed filings have been done to keep its organizational and tax exempt status up to date. From your description that seems unlikely.
In either event I would get an qualified and experienced attorney and CPA to assist in the organizational steps and the ongoing compliance requirements. The attorney normally helps you with the creation and organizational steps, while the CPA files the annual reporting forms including the 990 or 990 PF. Feel free to call if you need more specifics.
This answer is provided for informational purposes only. Actual legal advice can only be provided in an office consultation by an attorney licensed in your jurisdiction with experience in the area of law in which your concern lies.