Legal Question in Administrative Law in California

Employment is generally an "at will" relationship between the employer and the employee. The main exceptions are if you are working under a union contract or have a written employment contract assuring you of tenure. Also, it's generally unlawful for an employer to dismiss someone based on a condition such as race, religion, etc. However, there's no law or public policy against firing an at-will employee for a good reason, or for no reason at all. Therefore, unless the "something two years ago" involved protected free speech, union organizing activity, or something like that, it's very likely the employer acted within its rights both times. Can't say so for sure, but your question doesn't seem to suggest anything that indicates the employer acted improperly under the law or that you would be entitled to reinstatement or compensation.