"It's OK to buy, you can upgrade later ..."

Microsoft has kicked off its Vista Capable logo programme which identifies computers capable of running Microsoft's next-generation operating system and allows users to switch when it arrives in January 2007.

"Customers buying PCs today that exceed the Windows Vista Capable PC baseline are more likely to be able to take advantage of the premium experiences in Windows Vista when they upgrade," a Microsoft spokesman said.

Qualifying systems need to pass the current certification requirements for the 'Designed for Windows XP' logo.

They are required to offer 512MB of internal memory, a graphics card that supports Windows Vista Display Driver model drivers and one of several qualifying processors listed on the websites of Intel, AMD and VIA.

Microsoft first announced the logo programme at the WinHEC conference in April last year.

The software giant is preparing several versions of Vista, and the logo currently indicates that a system can run Windows Vista Home Basic.

Microsoft plans to release the hardware requirements for more advanced versions such as Premium at a later stage.