Global personal computer shipments rose sharply in the first quarter, according to industry estimates released on Wednesday, as businesses finally began to spend again on technology equipment.

Industry tracker IDC said PC shipments rose 24.2 percent in the January-March period to 79.1 million units, while Gartner put growth at 27.4 percent in the quarter.

The year-over-year rise looked especially robust in part because the first quarter of 2009 was so difficult, coming at the depths of the economic downturn.

But IDC analyst Jay Chou said the PC market performance was still notable in its strength, with good signs from markets around the world, particularly emerging markets.

It was very strong. We're seeing more hopeful signs of commercial buying, in addition to continued good consumer demand, Chou said.

After well over a year of depressed spending on technology purchases, businesses are widely expected to open their wallets, starting this year, as they upgrade aging IT hardware. IDC expects PC sales to rise 15 percent or more in 2010.

These first quarter results indicate that the professional PC market is gradually picking up, driven by PC replacements in mature markets, said Gartner analyst Mikako Kitagawa in a release.

Major PC replacement demand driven by Windows 7 will become more apparent in the second half of 2010 and the beginning of 2011, she said.

Hewlett-Packard Co retained the top spot in the global PC rankings, although its market share slipped to 19.7 percent, IDC said.

Fast-growing Acer Inc <2353.TW> continued to take share in the PC market, with shipments rising 43 percent. The Taiwanese vendor ranked No. 2 with 13.6 percent of the market.

Dell Inc , the third-place PC maker, saw a smaller share loss than in previous quarters. It held 13.3 percent of the market.

The strongest performance among the top five was turned in by Lenovo Group Ltd <0992.HK>. The No. 4 vendor saw shipments rise nearly 60 percent.

First quarter shipments from fifth-place Toshiba Corp <6502.T> climbed nearly 30 percent.

Apple Inc's computer shipments in the United States rose 8 percent, although the company lost share. Apple does not rank among the top five vendors globally, but it is No. 5 in the United States.

Overall sales in the United States rose 17 percent.

(Reporting by Gabriel Madway, editing by Leslie Gevirtz and Tim Dobbyn)