On his final day of testimony, Microsoft Corp. Chairman Bill Gates (news - web sites) was confronted with one of Microsoft 's own products -- Windows XP Embedded -- that does some things the company has said are impossible on its personal-computer operating system. Under questioning by lawyers for nine states that are pressing for tough antitrust restrictions on Microsoft 's business practices, Mr. Gates acknowledged that the software, a building-blocks version of Windows for small devices such as cash registers, might be used to create an operating system capable of running Microsoft 's Office application software.

Microsoft executives, including Mr. Gates, have said that the states' request for a modular version of Windows, from which programs such as Internet Explorer Web browser and Media Player audio-visual software could be removable, would be impossible. Mr. Gates has said that removing chunks of software code would cripple the operating system. During Mr. Gates's third day of testimony, the states' lawyers showed him company documents about Windows XP Embedded, which allows customers to pick and choose which functions their tailor-made operating system could perform.