fryed motherboard

i know this is off topic, but lets face it most programmers are very computer intelligent

when i went to my secondary computer it was off. Strange I never turned it off. I tried to turn it on. Nothing. I made sure everything was connected correctly. Yep. Nothing. I though ok bad power supply. So i ran to the store bought an antec 300w power supply put it in and it ran for about 20 secs then it started to smoke from a chip not cpu on the motherboard. Disconnected power asap from power supply. I took out all the pci, agp cards and the hd and the everything execpt the motherboard, cpu and one bank of memory. Turned it on and it started smoking a little bit more same place on motherboard. So i dissconnected it completely and came here.

Has anyone had a similar experience? Is it a defective power supply frying my mb? Is my hd fryed it was connected during the first smoking? Any thoughts

again sorry this is off subject, but i need help

The HD is probably fine, unless the short was directly on a circuit dedicated as a - on the HD ribbon cable.
I have never seen a Power supply take out the mother board, but I have seen a shorted mother board take out a power supply.
Typically, when power supplies go bad, they do not short circuit and therefore send a big spike down the line, or do something to cause the board to cook.
It is possible that you fried some of the cards and/or Ram. I would check them very closely for fried connections at the mother board and on the card itsself.
I have an old junk box around here that I use for just those kinds of cheks. I think I paid $40.00 for it a garage sale.
HTH
Michael

The answer is, "Hard to tell."

You will not know if anything else is damaged until you try it out.
Hopefully, nothing is damaged so that it would ruin the new MB.

Make sure you give all your components a good visual inspection
before using them.

good luck.

Most likely the motherboard...

Well it sure is dead now :D

The first cause of all this was your old PSU, so you've done the right thing to go buy a new one. Second, it affected your motherboard. So your new PSU did NOT work so well with your MB too. Best buy: New PSU + New MB. :) After that, if something does not work, one or more the other components got damaged by your old setup (CPU, AGP or PCI exp. cards).