Update: We are now able to login to Skype from our Windows Desktop Clients without any problem. Those who are facing problems, can find the fix for Windows & OSX platforms below.
Skype went down globally for brief period of time and at the time of writing this post, we’ve had trouble signing in to Skype using our Windows Desktop Clients. Engadget reports that Mac OSX clients, android and iOS clients had no problem. Skype confirmed the issue with following tweet - Some of you may have problems signing in to Skype and making calls. We’re investigating and hope to have more details to share soon. Skype tweeted again saying they have identified the problem and the following fix has been released -
Windows Vista and Windows 7
1.    Close Skype.
a.    Right-click the Skype icon in the system tray (at the bottom right of the screen)
b.    Choose Quit.
2.    Ensure that “Show hidden files and folders” is switched on.
a.    Click Start, type run and press Enter.
b.    Type control folders and click OK.
c.    Select the View tab and ensure relevant entry is enabled.
3.    Locate the shared.xml file.
a.    Click Start, type run and press Enter.
b.    Type %appdata%\skype and click OK.
c.    Delete the shared.xml file.
4.    Restart Skype. The shared.xml file will be recreated.
Windows XP
1.    Close Skype.
a.    Right-click the Skype icon in the system tray (at the bottom right of the screen)
b.    Choose Quit.
2.    Ensure that “Show hidden files and folders” is switched on.
a.    Click Start and then Run…
b.    Type control folders and click OK.
c.    Select the View tab and ensure relevant entry is enabled.
3.    Locate the shared.xml file.
a.    Click Start and then Run…
b.    Type %appdata%\skype and click OK.
c.    Delete the shared.xml file.
4.    Restart Skype. The shared.xml file will be recreated.
Mac OS X
1. Quit Skype.
2. Go to the folder ~/Library/Application Support/Skype/
3. Delete the file shared.xml (it will be recreated once you open Skype again, this is fine).
4. Start Skype.
Please note that the ~ sign means your home folder. You can find your home folder by opening Finder and selecting Go > Home from the menu bar or pressing Command (Apple), Shift and H keys at the same time.