Ever since Microsoft agreed to buy MediaOne's 29.7% stake in Britain's Telewest Communications back in May [see NewsSource, May 17 '99], the European Union Competition Commission has been investigating the deal's ramifications. On March 22, after extending its ruling deadline by two weeks, the EU announced that it will launch a full four-month probe into the agreement. The probe will especially look into Microsoft's relationship with AT&T's LibertyMedia, the other primary TeleWest shareholder, in addition to investigating clauses in the agreement that call for Microsoft software to be used on Telewest cable boxes. This investigation is unrelated to the EU's ongoing probe into Microsoft's potentially anticompetitive business practices.