Bill Gates told a conference of hardware developers yesterday that Microsoft had shifted 40 million Windows Vista licenses in the first 100 days the system has been on sale. "I'm really thrilled", said Gates.

Launched at the end of January this year, Windows Vista was the first major OS update from Microsoft in over 5 years. Over 90 percent of the world's computers run a Windows operating system.

It has not been a trouble-free launch with criticism over the confusing amount of different versions available, claims that it is very memory hungry and initial reports of it being buggy.

Interestingly Gates said that premium editions made up over 75 percent of sales and consumers wanting to enhance their digital lifestyles helped with the success.

Gates also revealed that Microsoft has now named the next-gen Windows Server software - codenamed "Longhorn" - it shall now be known as Windows Server 2008 and should be available late-2007.