Banyan Systems Inc shares plunged $9.875 or almost 40%, to $15.75 in the week before Christmas after the Westborough, Massachusetts network operating system company projected disappointing quarterly results: Banyan warned that its fourth-quarter results may fall below Wall Street expectations because customers are delaying their software buying decisions but profits for 1993 will still jump 50% and turnover will rise 25% from 1992; We are concerned that Banyan’s ills may be rooted in bigger network operating system industry issues and that it will take longer than the current quarter to cure this issue, said Ladenburg Thalmann & Co.