Steppers not have enough juice?

-I have posted this in reprapers a few days ago with no one able to help so I figured I would try a different thread if you can help that'd be awesome, if not thats alright too:

Ok so I am working on my reprap but I have invariably ran into the problem of my stepper motors making noise and not turning. They make a high pitch noise but don't seem to have enough torque or something to move. If I hit .1 it may move but if I hit anything higher it just makes noise. The vref is set right, In fact I set them higher to see if it would help to no avail. One thing I have noticed though is if I go into the firmware and change this line
#define _AXIS_STEP_PER_UNIT {80, 80, 3200/1.25,700} to lower values of x,y,z for example #define _AXIS_STEP_PER_UNIT {20, 30, 1000/1.25,700} the motors will work fine except I have to hit the .1 like 30 times in order to get it to move. But the problem is that the distances are all messed up so it doesn't really fix anything. I have also tried changing some of the acceleration and movement settings like:
#define _ACCELERATION 1000 <------TO-------> #define _ACCELERATION 300
and
#define _MAX_FEEDRATE {400, 400, 2, 45} <------TO-------> #define _MAX_FEEDRATE {100, 100, .5, 45

But this hasn't helped any either, so I am wondering if there is a power problem going to the motors or maybe the drivers?

Could the drivers be bad? Is there some way to test to make sure they work alright?

did you set the vref on the stepper drivers?
you can also download the test software [reprap.org] to see if things at least function.

Yea, I set them to around .5 and tried setting it higher with no change

That's the sort of behavior I got from one of my stepper motors when I cranked up its speed too much. Very short moves worked fine because the acceleration value kept the motor from ever hitting top speed, but for longer moves the motor would jerk and then just whine. Are those feedrates you listed in mm/s? If so, try turning them waaay down to start with, as in 10 or 20 mm/s.