Ok Thorarinn, please tell us exactly what printer you have. We can establish who/what is wrong when we know what is right.
You mention "SD mobo", there are a few generations to choose from!!
If you've increased Vref to max and tried to run motors, it is possible you have overheated your stepper IC's and killed them. This is unfortunate. Was there a reason to adjust the Vref initially? Was this tuning the printer up, or was there a fault already?
The typical Vref will be different depending on your board and motors, and can be worked out easily enough given enough information. More information than we currently have. Please disregard the large collection of values you've already been provided with (.3-.6V, 1V, .350V-.500V, 0.17V, 0.250V, 0.400V at current count... Any one of those could be right or even more likely wrong. GUYS, THIS IS CONFUSING!!).
Similarly as wardjr and carl suggest, I'm a fan of adjusting by ear too - the Vref = x.xxV thing really is just a starting point, often near enough is good enough. I doesn't take into consideration variation in motors and the mechanical system. Try that when you've got it working again. 
SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi