Nikon D80 Flash not opening all the way?

When it's set to automatic, manual, or any setting, the flash does not open all the way. It seems to open half-way. This cause the flash to not occur UNLESS i push it all the way up and then it will flash. It seems to stop at half way. It does seem a bit dry… Maybe I need to oil it?

Added (1). Yes the spring is still intact

You said it yourself, this might be a mechanical problem.
is the spring intact?