changing gear problem?

I have a vauxall opel corsa 1.2 + W reg. I was driving along no problem untill I had to change gear, I could only get it into 4th gear. I turned off the engine and restarted it, before changing gear it made a clicking or vibrating noise. then it went into gear perfectly well and the noise went away. starting the engine now it has the noise, then when I put it into gear it goes away again. Do you think I need a new gear box?

Dodo
May 2011