Lenovo, China?s largest computer supplier, announced a $1.75bn deal to buy the PC unit of IBM on Wednesday and warned Dell Computer and Hewlett-Packard, the world market leaders, that it would not be satisfied with its new position as the world?s third biggest PC supplier.

The deal - the biggest overseas acquisition by a Chinese technology company - marks IBM's exit from a market it created with the first IBM PC in 1981.