Microsoft will not support the more efficient Extensible Firmware Interface (EFI) in its forthcoming Windows Vista operating system.
The Intel-developed EFI is designed to replace the Basic input/output system (BIOS) that has dominated PC platforms for over 20 years.
Both systems give a machine its first instructions when it is turned on and allows the operating system to be loaded.
But the advantage of EFI is that it delivers shorter boot-up times and allows hardware suppliers to bundle device drivers that are independent of the operating system.
Microsoft had originally said it would support EFI on 64-bit systems, but has now back-tracked on its plans after saying there will be too few 64-bit processors on the market when Windows Vista starts shipping towards the end of the year.
Microsoft announced its change of plan at last week’s Intel Developer Forum (IDF) in San Francisco.
Microsoft has previously supported EFI in its 64-bit version of Windows XP, which is mainly aimed at PC enthusiasts. Apple is already using EFI in its new Intel-powered systems.