Microsoft confirmed on Wednesday that a number of its online sites are currently unavailable and have been down for a number of hours. Microsoft is temporarily experiencing problems with its various Web properties, including Microsoft.com, MSN.com, WindowsMedia.com, Encarta.com, Carpoint.com and Expedia.com, said Adam Sohn, a company spokesman. "Customers aren't able to get to some Microsoft Web properties," said Sohn. "We're working as quickly as we can to resolve those issues." Sohn said it was unclear how long the sites would remain offline. Microsoft sites in both the US and Europe appear to be affected. "We've heard some customers in Europe are having problems as well," said Sohn, who added that the outage may affect customers globally. Microsoft said that beginning Tuesday night and through Wednesday morning users have been getting no response from the affected Web sites. Sohn said the problem stems from Microsoft's Domain Name Servers, which translate requests to various Web servers. The servers are operated and maintained by Microsoft. The software giant, which recently suffered from an attack to its computer network, said based on its investigation, there is no reason to believe the current problems affecting Microsoft Web sites are related to any type of intrusion or hacking incident. "Right now our focus is doing everything we can to figure out how to get [the sites] back up and available in as shortest time as possible," Sohn said. CNET News.com has received numerous complaints about the lack of access. People said that for several hours Tuesday night and Wednesday morning they were locked out of a number of Microsoft Web properties, including news site MSNBC.com, Internet service provider MSN.com, free email service Hotmail.com and online travel site Expedia.com. Recently, a number of large Web sites have gone down, primarily because of server errors. Earlier this month, for instance, giant online auctioneer eBay suffered a day of lengthy outages. During the outages, eBay visitors could access the company's home page and its category listings but weren't able to view individual auctions, place bids or list items. eBay said the interruption resulted from a series of failures that affected the company's primary and backup systems. Last month, some Hotmail members were shut out of their email accounts for several days because of system upgrades to the free service. That was not the first time users of Hotmail, which is run by Microsoft, had confronted such problems: a similar outage occurred in 1999 when the company failed to pay a $35 (£21) registration fee for the domain name Passport.com. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read other letters.