Vanguard will reopen the Windsor Fund June 1, with Sanford C. Bernstein as an additional adviser. Bernstein will manage a smaller portion of assets than Wellington Management, the lead adviser for the $16.5 billion mutual fund. Bernstein was added to provide diversification without changing the funds character, according to a spokesman. It also provided the opportunity to reopen the fund, which has been closed since May 1989. Separately, James P. Barrow will assume the role of portfolio manager of Vanguard Selected Value Fund, succeeding James S. McClure, who has managed the fund since its inception in 1996 and will continue as lead manager of Windsor II. Both Messrs. Barrow and McClure are portfolio managers with Barrow Hanley Mewhinney & Strauss, the lead adviser to Vanguard Windsor II.