interesting indeed, the car stood for 5 days, on 6th day I got in car started her up , and all seemed great, then I tried to use 1st gear nothing! totally blocked all gears would not engage, at this point I felt a panic set in off $$$$$ , turned engine off, tried gears all working , then started engine - no gears. I tried to engage 3rd to create a stall, but just got a grind not good ! and prob silly to even try that. so turned engine off, clutch down into 3rd start engine lift clutch, and a stall occurred with another sound like a bang but nothing major. this cured the problem , gears all selectable no roughness or noise. so I take it for a spin , this is my question , 3rd gear bit notchy with hesitancy to go in- slight grind. all other gears are as were before.also 3rd isn't jumping out... do I have bent selector fork? or synchro problem? is this a new box or live with it??? . I don't see how they became stuck in first place ...

 

A long time ago my clutch did the same thing. I just stuck it in gear and turned it over I got to the end of the drive and the car fired up and there was a clunk/bang. Put the clutch in and it operated as normal. It never happened again.