I am unable to put car into gear, any ideas as to cause?

I am unable to put car into gear, any ideas as to cause? Car is 98 renault scenic. Can be put into 5th but nothing else! engine runs and clutch works with 5th buut will not engage other gears. was working ok then whilst doing 3 point turn was unable to engage gear! Any Ideas as to cause and/or fix?

mike b
November 2007