Motherboard or CPU dead?
The burning smell (if it was a fishy type smell) may have come from the mobo psu 21 pin connector where you plug in the psu.
The connection may not work properly because of melted plastic deposits which may be why you are unable to turn it off at the switch.
Just check the old psu connector for signs of rusting pins and mis-shaped connector.
If you have a fairly recent mobo and processor ensure that the power supply doesnt need the power supply from the psu, unlike some processors where the power is taken from the ZIF mobo socket.
Jan 18, 2007 |
EliteGroup KT400 (L7VTA2 V2.0) Motherboard