yeah that PSU seems kinda iffy, but if ur up to solving the issue, remove the Mobo from the case, place it on cardboard with an anti-static mat below, plug in all vitals (power 24/8) (power button/speaker) 1 stick of RAM, CPU w/ cooler, 1 video card w/ power if needed, and main HD... if u have integrated video go with that instead...
boot er up see if it works...
If you get any beep codes from the speaker refer to user manual... and that will mean ur Mobo is not dead...
remove RAM boot, you should get an error code, because u have no ram...
if that doesn't work, unplug PSU from wall, remove CMOS battery, move CMOS reset jumper, and leave overnight, in morning replace and boot again...