Well, **** like this does happen once in a while.

Again, why I said to test with nothing but CPU and memory hooked up as you narrow down what parts could be bad. Guess you tried to use the other memory chip.

Next would be to try your CPU in another board if you could, or your MB with another CPU.

And check the power supply with a VOM.
There are plenty of articles on how to do it. Just remember, an ATX power supply will not work unless it is connected to the motherboard ( which I don’t like to do ) or you have to short pins 14 & 15. Maybe your instructor can help you with this if you have never used a VOM.

Sorry you are having these troubles.

Well, back to work for me.