Need help quick! 3D printer test troubles, motors non moving (m999 and more)

Hi! I've been recently building a 3D printer and I'm having issues testing it.This is my hardware:
Ramps1.4
Arduino mega2560
4x Pololu Motor shields a4988
1x Nema17 extruder
2x floppy stepper motor
1x DVD stepper motor
Generic hotend with 0,4 nozzle
Then I assembled everything and I started testing... I tried ramps test code and it didn't work (motors did not move, but I'm sure they are ok), then I tried using marlin and pronterface; it showed hotend temperature stuck at 150 degrees, but the hotend was not hot. Moreover motors would not move.
I also tried repetier host and it returned me a m999 error without any further explanation.
I had no problem installing firmwares on the arduino and the fan of the hotend is working. I also tried changing baud rate but it seemed not to work.
I need a quick help since this is a school project I need to have a working printer before next week (13 days max). I'm asking for a fast solution to this problem.
Thank you in advance and sorry for my bad English.

This is a picture of the hardware Attachment 10337

1st, I would say that you have chosen the wrong thermistor in Marlin setup if it is reading 150 at startup. Start by disconnecting everything from the ramps board and add back in 1 axis at a time. Make sure that your endstops are connected properly. You should be able to get x,y,and z axis all working before tackling the hot end and bed. Good Luck