Microsoft's strong earnings report today was fueled by solid sales of Windows 7, but digging deeper into the numbers, it's clear that many of the company's businesses have seen better quarters. Despite a a big in advertising revenue, increased expenses pushed the company's online business ever deeper into the red. And Microsoft's business-software units continued to show the effects of sluggish corporate spending.

Here's a division-by-division breakdown of the results.

Windows and Windows Live: The big bright spot for the company this time around, this division was boosted by rising PC sales, estimated to have grown by 25 percent worldwide last quarter. Microsoft says the unit growth was biggest -- about 30 percent -- among consumer PCs. But unit sales of PCs to businesses were up about 14 percent, and Microsoft said corporate customers have started spending on hardware again.

Operating profits were up 35 percent in the division for the quarter, topping $3 billion. Interesting factoid from the company's quarterly SEC filing: "Sales and marketing expenses increased $105 million or 23% reflecting increased advertising and marketing of Windows 7 and increased sales force expenses related to Windows 7."

Server & Tools: This division, which includes Windows Server, SQL Server and related products, was once renowned for stringing together consecutive quarters of double-digit revenue growth. No more.

Revenue was up a mere 2 percent in the quarter, to $3.58 billion. That was less than the $3.8 billion that analysts with Goldman Sachs had expected for the quarter, one of the factors prompting them to voice caution about the pace of the corporate tech spending recovery. Operating profits rose 3 percent, to $1.26 billion.

Microsoft Business Division: Same story here. Reported revenue of $4.25 billion was down 6 percent from the same quarter last year. That resulted in part from Microsoft's deferral of $305 million in revenue from the quarter because of Office 2010 upgrade promotions that prevent the company from recording the sales until after the new product is available. But even adjusting for that, the growth in this division was a relatively modest 1 percent, thanks to relatively weak business spending.

Interesting factoid from this division: Sales and marketing expenses fell $71 million, or 7 percent, according to the company's SEC filing. Look for that to ramp up significantly as the company preps for the release of Office 2010 and related products, starting with its debut for businesses next month.

Entertainment & Devices: This division swung to a $165 million profit thanks in part to the declining cost of making Xbox 360s, a common phenomenon later in the hardware life-cycle, as companies start to see manufacturing efficiencies. Revenue in the Entertainment & Devices division rose 2 percent, to $1.67 billion, thanks in part to rising revenue from the Xbox Live online gaming service.

Also helping significantly was an increase of $77 million, or 14 percent, in non-gaming revenue, primarily sales of Windows embedded device platforms and PC hardware products, such as keyboards and mice.

The company shipped fewer Xbox 360s overall -- 1.5 million units, compared with 1.7 million in the same quarter last year, which Microsoft described as in line with an overall decline in the market.

Online Services Divison: OK, so here's some good news for the company: Online advertising revenue was up 19 percent, to $502 million, which Microsoft credited to an increase in search revenue. That's a rare brght spot in the company's long struggle against Google in the market for Internet search advertising. Microsoft's Bing search engine has been making steady gains, reaching 11.7 percent of the U.S. market in the latest comScore numbers.

But here's the bad news: Despite those gains in revenue, the company's online business showed an even wider operating loss, $713 million, as a result of expenses related to its Yahoo search partnership, sales and marketing costs, and traffic acquisition costs. As we've explained in the past, that last category of costs includes the payments Microsoft makes to PC makers that distribute Bing as the default on new computers -- which is one of the reasons Bing's market share is rising, and ad revenue is going up.

In other words, nothing is free. And so far, Microsoft is spending more online than it's getting in return.

Earlier: Microsoft: Record revenue, Windows 7 reaches 10% of PCs