My excavator's boom will not operate?

Hi,
I had the same problem with the boom not moving to the left so I replaced the whole valve block! Now everything works fine but the boom. I can not get the boom to move up only down. I have removed nuts and pushed on the joystick , hydraulic fluid only oozes out. It's like the hydraulic fluid isn't being pushed to the ram. What could this be?

Kassie DeRosier
August 2011