Summary Box: Hewlett-Packard buying network security company ArcSight for $1.5 billion

Summary Box: HP buying ArcSight for $1.5 billion

THE DEAL: Hewlett-Packard Co. has agreed to buy the network-security company ArcSight Inc. for about $1.5 billion.

THE STRATEGY: HP wants to have the answer to all of its customers’ technology problems. It is buying ArcSight to help customers respond to the growing security threats.

THE BACKDROP: The deal could help HP prove that even after ousting CEO Mark Hurd, it hasn’t lost its footing in the effort to win fatter profit margins beyond the personal-computer business.