Psp disk reading problems

I have a pretty strange problem with my PSP. Recently it stopped reading disks so I took it apart and cleaned the laser then I put it back together and tried it again and it still would not read the disk. So I went and took the front cover off of the psp and then tried a disk in it and the umd loaded up and was working.

I have narrowed it down to the analog stick being the problem, every time I put the analog stick back in the psp were it is suppose to be the game with stop and the umd wont load up again, then when I remove the analog stick it works perfectly again.

Does anyone know how I would fix the problem.

Thanks