SAN JOSE, Calif. — Microsoft Corp. has taken the rare step of warning about a serious computer security vulnerability it hasn't fixed yet. The vulnerability disclosed Monday affects Internet Explorer users whose computers run the Windows XP or Windows Server 2003 operating software.

Palin offers comments over Twitter, FacebookANCHORAGE, Alaska — Sarah Palin is communicating through social networking sites after her surprise announcement last week that she will resign as Alaska governor.

Global ad spend still to fall, signs of bottomingA key advertising forecaster said Monday that global ad spending shows signs of reaching bottom as some sectors held up better than expected during the second quarter.

China state media says 156 killed in riots in westBEIJING — Chinese state media says that 156 people have been killed in violent riots in the country's western Xinjiang region.

Ethnic riots spread in China's west; 140 killedURUMQI, China — Riots and street battles killed at least 140 people in China's western Xinjiang province and injured 828 others in the deadliest ethnic unrest to hit the region in decades. Officials said Monday the death toll was expected to rise.