Microsoft won a $478 million, six-year contract to provide software to the U.S. Army, the biggest order ever for the company"s programs.
The agreement covers 494,000 desktop computers, Microsoft spokesman Keith Hodson said.
The Defense Department has questioned the security of Microsoft and rival products in the wake of the Sept. 11 terrorist attacks. One of the department"s server computers was attacked in March using a flaw in Microsoft"s Windows program.
The contract shows the Army has decided that Microsoft"s security is sufficient, said Rob Enderle, an analyst at Forrester Research.
Microsoft is trying to boost sales to federal, state and local governments that are spending to combat terrorism and improve security. The company has lost some government contracts outside of the U.S. to the free Linux operating system, and it has been working to assure the U.S. government and defense department that its programs are secure.