Skype freezes computer

Every time that I try to sign into Skype, my computer completely locks up. As soon as I enter my user name and password, and push the Sign In button, my mouse stops working, my keyboard stops working and I have to power down my computer to be able to use it again. Even Control/Alt/Delete does nothing.

I complained to Skype about this problem and they suggested that it was a problem with my operationg system (Windows 7 Home Premium 64 bit). Since then, I have reinstalled the operating system. All updates have been installed. I have set exceptions for Skype in my Firewall.

The program loads OK, it is just when I sign in that it locks up.

Google Talk works perfectly on my machine.

No other programs cause this error.

I found one other EE question about this, but there was no accepted answer (forced close), so I am not alone.

I'd appreciate any help that you can give me.

Brian