Microsoft is considering releasing an update to Windows XP prior to the 2006 launch of its Longhorn operating system.

But it is not yet clear whether the update, Windows XP - Reloaded, will be a service pack or an interim release.

A spokeswoman for Microsoft would only say: "Reloaded refers to efforts being made to add value to the XP platform."

Microsoft has come under increasing pressure to ship some form of update, having pushed back Longhorn's scheduled release from 2004 to 2006.

With a final shipping date for Longhorn still some way off, the company risks open source alternatives to its desktop operating system gaining ground.

When previously faced with long intervals between major releases, Microsoft pushed out Windows 98 Second Edition.

"We look forward to outlining details [of Reloaded] but at this time we don't have anything further to say," the company said in a statement.