How to reverse motor's and other beginner questions

So i got my 2 broken stepper drivers back, and after some tuning they are now working,
and i now have a machine that moves X,Y and Z and heats the extruder and reads the temp correct.
The extruder stepper still isn't turning, but makes a high pitched noise.

The X and Y axis however move to the other side of where i placed my endstops,
and because i don't want to move my endstops i want to turn both X-Y axis,
if i turn them both the print will be the same i think.
they are now connected like this:
A= blue
B= red
C=green
D=black

so what should i turn?

as for the extruder driver, is there a way i can connect only 2 wires (safely) to see if maybe something is wrong?

and then a last question, i use the standard software on a very simple net top pc (1,6 ghz, 1 gb ram)
and sometimes the software freaks a goes in endless loops and i have to re start.
do i need a faster PC or should this be fine?

thanks

To reverse direction of the axis, you can do one of the following:

1. The simplest way is to reverse the connector on the controller end. Ex. +A-A-B+B becomes +B-B-A+A
2. You can make the change in the firmware.

Your PC is probably the bottom end of what is useable. It is similar to my setup. It creates enough problems for me that I am considering getting something more powerful.

The high pitched extruder stepper may be thousands of missed steps from trying to run too fast. That's what happens to me when I accidentally try to run the extruder at Repsnappers' default of 3000 instead of the 150 or so I need.