Skype crashed last week and I have been unable to get restarted. Please help.

Millions of Skype users were unable to make calls for several hours on Wednesday because of technical problems that the Internet telephone service is still trying to fix.

Some users were unable to log in. For others who were already logged in, the service simply crashed.

Skype said in a blog post that it started investigating the problem after noticing that the number of people on its service was unexpectedly falling. Fixing the problem may take several hours, the company said, adding that it may be longer before other features like group video calling are restored to normal.

The troubles come as Skype, which spun off from eBay last year, prepares for an initial public offering. Meanwhile, Tony Bates, Skype's new chief executive, is trying to find new ways to make money outside the company's main business of charging users to call from their computers to landline and mobile phones.

The failure does not exactly help Skype's sales pitch to consumers as an alternative to traditional phone carriers. Nor does it reassure businesses, which Skype is trying to court as customers as part of its expansion plans.

Usually, Skype's service is problem-free.

Skype said the downtime was being caused by "supernodes," which are computers that "act a bit like phone directories" and enable callers to connect with others. Many of those "supernodes" - of which there are normally a large number - were taken offline by a problem with some versions of Skype's software, the company said.

Engineers are working to create "new 'mega-supernodes' as fast as they can, which should gradually return things to normal," Skype said.

Later on Wednesday, Skype posted a message on Twitter saying that its service was gradually returning to normal, but that it would still take several hours for all users to be able to sign in again.

Skype has 124 million active monthly users, as of June 30. Of those, only 8.1 million pay anything.
Mr. Bates has described himself as a fan of Skype's infrastructure, which has handled as many as 25 million users simultaneously.