PC Help- Mobo dead. I give up.

[SpaceBooger]

So yesterday I got a proper CPU (Athlon x2 2.3), put it in and nothing happened.
I pressed the power button and it wouldn't turn on - not the fans not anything. If I held the button it the internals (CPU fan, Case Fan, and GPU fan) would run. After trying this a couple times I figured it may be because it's a more powerful CPU and needs more power, but not as powerful as the original.

After about 2min of playing around with it (trying to boot it multiple ways - holding the button for different lengths of time) the I started to smell the electric burn smell and the power supply does not work. So the power supply is dead.

Should I try another power supply? I already tried holding the mobo up and hooking it to another power supply that was in another case, but it wouldn't boot - its an older supply from around 2002 and the mobo wasn't in a case. So I don't know if I should just give up or spend money on a new power supply?

My new questions:
1. Can a faulty cpu or motherboard ruin a power supply? Maybe the power supply was the problem all along.
2. Can a faulty power supply ruin a motherboard? I ask because I have another working pc but would need the power supply to replace the 300w one so I could install the pcie graphics card and I don't want to ruin the only working power supply I have.

I ask these because I don't know where to go next and don't want to ruin a new power supply. Any advise would be appreciated.

[Hobie-wan]

A problematic power supply can definitely break other stuff. Problematic other stuff could break a PS, but it is a lot less likely unless there's a catastrophic failure on the mobo and the PS is cheap and not made with the appropriate failsafes in place. Try this with the PS all by itself. Unbend a paperclip and insert it to connect the green wire to a black one on the plug block that goes to the mobo. If you're concerned about fiddling with it since there are other live wires there, you can do that with it switched off, then switch on with your hands off the paperclip. That will make the PS think it's in a PC and come on. So see if the fan spins up and if you get the burning smell still.

[SpaceBooger]

Ok, so I did the paper clip thing and the green light on the back lit right up and the fan started to run.
So it is safe to say the motherboard is bad right? Or should I still try a new power supply with it?

[Hobie-wan]

Well, that tells you the PS isn't completely dead. Was kinda hoping it wouldn't fire up or still filled the room with bad smell so we'd have a good idea that was the problem. The PS could still be an issue, but it's ok enough to fire up when it isn't really having to do anything but power up the fan and the led. If you have another PS that you can use long enough to test the mobo and stuff I'd do that next.

[SpaceBooger]

I appreciate all the help, but I'm going to give up.
The other PSU wouldn't work, so its the mobo. I don't want to buy a new mobo since the cheapest one I found is $30. I would pay $30 if I knew the quad core Phenom worked but I don't and I dont want to spend that to run an outdated dual core Athlon 64.
Again, thanks for the help.