Not a problem, let me know how it turns out.
On the flip side, you can also see if your friend will let you put your motherboard into his computer using his HDD, PSU, and GPU. Don't worry about drivers, this is just to see if it boots at all.
Also run a memory diagnostic, by removing all RAM and trying to turn on the computer. If nothing still nothing, put one stick into the first slot and try it again. If nothing, swap with another stick. If nothing, then RAM might be okay.
One thing that may have happened is that your old PSU went out, and when it went out it took your motherboard with it. If this is the case, you RAM may have been damaged as well as your GPU. While this is rare and there are safe guards to prevent this, it can still happen.