the analog input did not seem to be working correctly, so i attempted to test it by supplying voltages from a power supply and potentiometer to see if it gave the right values.
So what voltage did you feed the pot with? The arduino can not stand any more that 5V.
the power supply was putting out half an amp at almost zero voltage
That sounds like the over current limit was kicking in and you were feeding the power supply into a dead short.
Unless you put in greater than 5V it looks like something else killed your input pin.