Make sure that you're running Windows XP, SP3, 32 bit. If you're not meeting this requirement, it could be why it's not working. You could also try reinstalling Skype to be sure that you don't have a corrupt installation and be sure your firewall isn't causing any issues.
Here's a full list of system requirements:
|
Skype for Windows Desktop |
|
Version |
Windows XP SP3 (32-bit version only)♦
Windows Vista
Windows 7 (32-bit and 64-bit versions supported)*
Windows 8
Windows 8.1
|
|
Processor |
At least 1 GHz |
|
RAM |
At least 512 MB |
|
Additional software |
DirectX v9.0 or above |
