Former HP chief executive Carly Fiorina on Tuesday took the first formal step toward running for Democrat Barbara Boxer’s U.S. Senate seat. Fiorina filed for a tax identification number Tuesday and registered a campaign committee named “Carly for California.” The committee will allow her to begin raising money for a potential 2010 run for the Republican nomination. In a statement, Fiorina said she had been encouraged to run by “people across the political spectrum” and will begin meeting with policy advisers and financial donors.