It seems odd to use URLs to launch apps. I wonder if you meant the path and the name of the app?

More about URL -> http://en.wikipedia.org/wiki/Uniform_resource_locator

My guess is the association for the shortcut or .LNK has been hijacked. This is very easy to solve as we use system restore to the day before the issue.

If malware is involved, you remove that too. Need deeper details? Read
http://answers.microsoft.com/en-us/windows/forum/windows_7-files/in-windows-7-lnk-file-associations-changed/024cf5f6-9777-4615-a9ae-b8d914e2f277

Bob