If it's an SLR, check whether the shutter open or not.
I've got a 2nd hand SLR with shutter problem (some grease on it)
So I test a roll with various shutter speed - none came out.
and discover that the shutter did not open. Some sticky stuff. No choice had to send in to service.
For your X700 (nice cam :thumbsup: ) the film rewind knob will spin every time you advance the film (if it is correctly loaded) - I also believe the X700 has another indicator to signal correct film loading - check your manual