Microsoft Windows Vista has gone on sale for consumers across the World. 100 million computers are predicted to be running it within a year. But many PCs will be too slow to cope. The BBC's Technology team have put Vista through its paces and sampled reaction of those using it.
1.VISTA IN ACTION
Vista boasts 3D graphics, improved searches for files and a new pop-up system tray.
But some computers will be unable to run it - Microsoft recommends PCs have at least 512Mb of RAM, an 800Mhz processor and 15Gb of hard disk space.
BBC Technology Correspondent Mark Ward puts the operating system through its paces.
2. VISTA'S SECURITY FEATURES
Vista brings new ways of protecting computers from viruses and con artists intent on stealing personal details.
It sends out repeated warnings if its in-built security settings are switched off.
BBC Technology Correspondent Mark ward investigates "anti-phishing" and automatic protection in Vista.
3. INSTALLING THE UPGRADE
Just how hard can it be to upgrade to Vista?
BBC News website Technology Editor Darren Waters found a few pitfalls when he replaced Windows XP with Microsoft's latest operating system.
And even when he had jumped through all the hoops, it was quite some time before Vista was up and running.
4. THE TEENAGE TESTERS
A group of London schoolchildren has spent a week trying out Windows Vista and Apple's OS X.
So does familiarity keep them clinging to Windows, or does Apple give them the biggest buzz?
And do they think Vista's worth all the fuss?
5. BILL GATES THE SALESMAN
Bill Gates has been interviewed by BBC News on the release of Vista.
What security improvements are there? Why are there price differences between countries?
Watch the full interview between Mr Gates and Ten O'Clock News presenter Huw Edwards.