Hewlett-Packard (HP) will release a laptop next month that can run for to 24 hours using a high-capacity battery -- but only if it's running Microsoft's Windows XP operating system.

The long-lasting notebook will be a special configuration of the 6930p, part of HP's EliteBook line that the company targets at businesses.

The allure of a battery that can last a day is incontestable, as anyone who has spent time in an airport searching for a power outlet knows. The secret to the 6930p's long battery life is new technology -- and some old technology too.

To get the best battery performance, the 6930p will have to run Windows XP rather than Windows Vista, Microsoft's latest operating system. Vista has been criticized as being a power hog, although some of its flashy, power-draining features such as the translucent Aero windows can be turned off.

Although Microsoft has been heavily pushing Vista, HP has said it will offer downgrades from Vista to Windows XP on business laptops through next year.

The 6930p will also need a 12-cell Ultra-Capacity Battery, which sells for US$189. The battery lasts about 10 hours longer than the regular-capacity one.

The new laptop model will also have HP's Illumi-Lite LED (light-emitting diode) display, which the company says adds four more hours to a battery's life than a traditional LCD (liquid crystal display) screen.

Further power savings will come from the use of an Intel SSD (solid-state drive), which uses power-saving NAND flash memory rather than a rotating magnetic disk to store information. Use of an Intel SSD enables the battery to last around 7 percent longer, HP said.

HP is one of Intel's partners and will soon being incorporating Intel X25-M and X18M Mainstream SATA SSDs in its products.

HP lists the current available version of the 6930p as starting at US$1,199 on its Web site, although the company has not listed how much the 24-hour battery life configuration will cost.