hey - thanks for all the suggestions - i looked at the wiring to the heater/ thermistor - i put an ohmmeter on the thermistor where it connects to the board while moving the bed back and forth - the resistance did jump a little bit (1-3 ohms) - it seems those wires crossed directly over the led on the plate - while i didn't see any open wires on the thermistor leads if i moved them right where they went over that led the resistance would change - i moved those wires an inch off the led and re-taped - the jumping of the resistance stopped - as i said i went through and removed all programs and registry entries in windows - so i reloaded a newer version of repetier/slic3r and tried a sample print of a cube - it did print correctly but rough - i tweeked some slicer and printer settings (this time i saved the original setting though) - the result is that it prints as good as it did before all these problems - so i'm back up and running - i'm going to try some of the programs suggested here and see if they work better than the sketchup/repetier/slic3r combination i'm using now - i've run into this before ..where windows "remembers" something in the registry and screws things up, especially when i repeatedly install and remove a program - hopefully it's all good now - thanks for all the advice