The demand for Windows Vista and the videogame Halo 3 helped lift Microsoft's sales by 27 percent during its first fiscal quarter, which the company says was its fastest growth for that three-month period since 1999.

The software giant brought in $13.8 billion in revenues for the quarter. Net income grew 23 percent to $4.3 billion, or 45 cents per share. The results easily surpassed Wall Street expectations, which called for $12.6 billion in revenues and 39 cents per share in earnings.

The company cited strength in its sales of the Windows Vista operating system to both businesses and consumers. But Microsoft also performed well outside its core business during the quarter. It nearly doubled sales in its entertainment and devices division, to $1.9 billion from $1 billion a year earlier.

During the quarter, Microsoft made its biggest-ever acquisition with a $6 billion takeover of aQuantitive, an online advertising company. And yesterday Microsoft announced that it had bought a $240 million stake in the social-networking site Facebook.

Investors rallied in after-hours trading. After closing up more than 2 percent during market hours, Microsoft shares soared another 6 percent after its earnings announcement. The news seems to have put an end to a sluggish year for its shares.