Lenovo was the only PC vendor among the top five that increased its unit sales during the fourth quarter, as the Western European PC market shrank by almost 12% year-on-year.

Research company Gartner said mobile and desktop PC shipments in Western Europe hit 15.3 million units in the fourth quarter of 2012, a decline from 17.4 million during the same period in 2011. The decrease in the professional PC market was 4.9% and the consumer PC market declined 17.6% year-on-year.

Lenovo sold 23.2% more PCs during the quarter than a year earlier, while unit sales at HP, Acer, Asustek Computer and Dell all fell.

HP is still the largest PC maker in Western Europe by a wide margin, but the company's market share dropped to 21.5% as it sold 3.3 million units, a drop of 8.8%.

Acer and Lenovo each had a market share of around 11.4%, but Acer sold 8,000 more PCs than Lenovo, according to Gartner's data. A year ago, the gap was 679,000 PCs.

Lenovo's effort to increase market share helped it take second place in the professional PC market. It also grew unit sales by 65% in the consumer PC market, according to Gartner.

Asus sold 1.7 million units in the quarter, 8.4% down on a year earlier.

Dell is now in fifth place, with shipments in the consumer PC market nearly halved compared to the fourth quarter of 2011. Overall, unit sales shrank by 21.9%, the biggest drop among the top five. Dell was also under pressure from HP and Lenovo in the professional PC segment, where both vendors focused on gaining share.

PC shipments in the UK reached 3.1 million units in the fourth quarter, a 0.7% decrease compared with the same period in 2011. In France, on the other hand, unit sales dropped by 13.6% to 2.5 million units.

In 2012, PC shipments in Western Europe reached 58 million units, a decrease of 8.4% from 2011.

This is the second consecutive yearly decline, indicating that the issues the PC market faces go beyond a weak economy, a poorly understood new operating system in Windows 8, or ultramobiles being priced too high to generate demand, according to Meike Escherich, principal research analyst at Gartner.