I suppose it would be silly to ask if you have any electronics experience. Let me approach this with an analogy. Suppose you're driving your car one day (if you had one I mean) and all of a sudden it stopped working. Would you get out of the car and start swapping components ? Do you see my point. Obviously something is wrong. How should you solve this problem. I did not see any mention whatsoever in your post that you immediately proceeded to dismantle your circuit and test every component one by one with a meter and then removed all the wires from the breadboarded and started over carefully checking the wiring as you went along. Clearly there is something wrong. Is the arduino ? If it were would you know how to test it ? If it even occurred to you to test it (not that it ever would mind you ) how would you go about it ? What is that 470uF capacitor for ? Any ideas ? Have you tested all the components ? Do you know how to ? Do you have a meter ? Did you post your code with your original post ? Are we to assume that the code in your IDE is in fact the same code in the link ?
Oh yeah, I test my motors by using my parallax PING sensor. Basic code, spin forward when distance > 12 inches and reverse when distance < 12 inches.
How can they be working if you just said they are not turning ? Did you mean you tested them before you had the problem ?
Did you measure the current after the problem occured ?
My motors are 12 VDC .09A 6.8RPM No load.
Is this what they should be ? Is this what they are now that it is not working ?