Microsoft did a great job getting out the word about Windows Vista, a Harris Poll published Wednesday said. But the marketing blitz hasn't generated big sales.

According to an online survey conducted by Harris Interactive, 87 per cent of the 2,200 American adults polled said they were aware of Vista; The overwhelming majority of those people admitted to knowing "a little" about the new OS.

But apparently knowing does not mean buying. In December 2006, 20 per cent of respondents said they were planning to upgrade to Vista; by mid-March, six weeks after Vista's retail roll-out, 12 per cent said they would migrate in the next 12 months.

More of those planning to move to Vista in the coming year will upgrade their existing computer than buy a new PC with the operating system pre-installed, said the survey. March's results differed slightly from December, in that more – 48 per cent compared to 39 per cent – said they would upgrade what they have, while fewer – 31 per cent versus 35 per cent – planned to buy new hardware to get Vista.

As of 6-14 March, when Harris polled, Vista accounted for just 3 per cent of the operating systems installed on the respondent's primary home computer, the same percentage as the often-reviled Windows Me. Leading the pack by a huge margin was Windows XP, with 79 per cent; Apple's Mac OS X, meanwhile, accounted for 5 per cent, the same as Microsoft's Windows 98.

The one bright spot for Microsoft and its OEM partners is that one in five of those polled said that Vista has convinced them to buy their next computer earlier than they had originally planned.

In other words, Microsoft has its work cut out for it. "Microsoft will have to put forward a value proposition that will move the majority to the upgrade category in the years ahead," said Milton Ellis, vice president of Harris' technology group. "Microsoft has faced this challenge before with operating system upgrades. Consumers tend to wait until a few service packs have been released to fix real or perceived problems."

Although Microsoft has touted sales of 20 million copies of Vista, analysts have pointed out that the company counts those that have been shipped to retail but not sold, or sold to OEMs but not installed on PCs or installed on PCs still in inventory.