Software giant Microsoft recently admitted that its Windows cash machine is under threat as its sales are suffering a fall.

Microsoft's net income jumped 155 per cent on 147 per cent higher revenue during 2001 to 2010. But following the announcement of dip in Windows operating system sales, shares in Microsoft slipped to close at $26.71 on Thursday.

On Friday, shares in Microsoft shed 4 per cent to $25.63 in afternoon NASDAQ trading, before recovering slightly to close at $25.92.

Over the past decade, shares in Microsoft generated a total return, together with dividends, of negative 0.2 per cent.

The PC market slipped 1-3 per cent during the March quarter as tablets are encroaching on the PC market. Windows sales are come down largely due to lack of Windows-powered tablets in the market. Windows' revenue dropped 4.4 per cent, while operating profit suffered a fall of 10 per cent.

Microsoft stock slipped 18 per cent over the last one year period, but analysts are of the view that the company will be able to overcome fall in the PC sales.

Meanwhile, Microsoft has rolled out a tool to encourage iOS developers to create and port their apps to Windows Phone 7.