Castleton State College said Tuesday that it had replaced its head football coach after an investigation into charges that he broke National Collegiate Athletic Association rules by helping a player get $22,000 in student loans. The Vermont public college said that the coach, Rich Alercio, had been accused by the NCAA of arranging for a part-time employee of the college to co-sign or endorse three loans for an unidentified player, which would violate the association's rules against improper benefits for athletes.