If Microsoft Corp. doesn't do more to stem Internet attacks, the company risks further alienating customers unhappy with the multitude of threats already facing its ubiquitous software.

Sell its own security products, on the other hand, and Microsoft faces a potential backlash from some of its allies -- the companies that now provide an extra layer of security for its Windows operating system, Internet Explorer browser and other products.

Decision to sell antivirus products places Microsoft in quandary