GEARBOX WONT GO INTO GEAR

Hi from uk could you please give a little more info ? what make/model car ? has this problem occured suddenly? has car been layed up off road some time prior to this unable to select gears ? this problem sounds very much like the clutch drive plate is either stuck to flywheel hence question above ? or it is sticking on primary/spigot shaft for some reason and failing to disengage drive to g/box? how does clutch pedal feel ? you might try selecting 2nd gear with clutch fully pressed and h/brake on then try starting engine if engine starts ?runs then put slight revs on and slip clutch a few times this may work if plate is sticking? if you come back with update may be able to advise further

How was the hydraulic clutch system bled? These things can be nearly impossible to bleed using conventional "you pump and I'll work the bleed valve" method. Many pro mechanics are not very good at it either.
Here's the trick: Get yourself an extra large "turkey baster" sized syringe(no needle) and about a foot of surgical tubing. Open the cap on the master cylinder and FILL IT UP-don't worry about the "full" marks. Go under the car and locate the hydraulic slave cylinder on the side of the trandmission. It will have a brake line running to it and the end of it sits against the clutch release lever. Find the bleed screw on the bottom of it and fit the surgical tubing over the end of it. Fit the other end of the tubing over the end of the syringe. Carefully loosen the bleed screw about 3/4 turn. Pull the plunger back on the syringe and observe the fluid as it fills it. STOP when it is 1/2 full!! Tighten the bleed screw back up, disconnect the tubing and squirt the fluid into the reservoir(will be nearly empty-it only holds about 1/3 cup!). repeat this 2-3 times until NO BUBBLES come into the syringe. Tighten up the bleed screw, replace the cap on the reservoir and that's it- you are done! On many cars, this is the ONLY WAY to get the hydraulic clutch to work properly. Good Luck!