Diagnose Power Up Problem??


My G4 867 DP- MDD has an intermittent problem. Sometimes when I push the power button....nothing happens at all...no light, no nothing....Others it powers up normally and I have to leave it on and just put it to sleep instead of powering down....Could this be a power button issue or is there something else I could try!!! And if it is the power button, is that a user fixable issue? I am not a tech, but have installed memory, hards drives..etc.. Thanks for any help!!! My Applecare is over and I can't really afford large repairs....