Skype has encountered a problem when logging in

Hi Friends,
Whenever I attempted to sign in SKYPE, i.e. as SKYPE begins to launch I get an error message, saying
"SKYPE has encountered a problem and needs to close".
And then the SKYPE doesn’t get started. I have already tried to solve this problem by uninstalling and then installing it again. But nothing works.
Please help me to solve this problem. I am using Windows XP as the operating system.
