The computer, which contains personal information on 38,000 veterans treated at VA medical facilities in Philadelphia and Pittsburgh, went missing from the Reston, Va., office of Unisys, the subcontractor hired to assist in insurance collection for those facilities. Unisys publicly acknowledged the computer's disappearance last week.

Unisys is now working with the VA's Office of the Inspector General and FBI officials to try to determine what happened to the computer.

In a separate incident, Chevron Corp. is searching for a password-protected laptop stolen on Aug. 5 from an independent accounting firm working for it. The laptop contained the names and Social Security numbers of an undisclosed number of current and former Chevron employees, according to a statement from the company e-mailed to Computerworld.

The accounting firm, which was not identified, was analyzing data as part of Chevron's regular efforts to demonstrate compliance with federal regulations governing employee-benefit programs, Chevron said. The theft has been reported to the appropriate authorities, and the San Ramon, Calif.-based company stressed that the laptop does not contain any information relating to its customers or transactions of any kind.

On Saturday, Chevron began notifying all current and former employees who could be affected by the theft. The company also provided credit-monitoring and identity-restoration services to all individuals who choose to use them.