Richard Schulze, the founder of Best Buy, is exploring putting together a bid to take the struggling electronics retailer private, according to people briefed on the matter. Mr. Schulze, who resigned from the company’s board this month, has been begun working with bankers from Credit Suisse to consider such a move, these people said. They said he would probably team up with a private equity firm or other deep-pocketed investor. With a 20.1 percent stake, he is the company’s largest shareholder.