wow - tough one.
Well here's what - give your mobo a drain - put the Cmos jumpers on reset, and plug off the PSU completly.
Leave it for a few hours.
In the mean while you can get an old toothbrush and brush out the RAM and PCI slots thoroughly.
+ take an erasor(normal erasor - preferably the rubbery ones, rather than the more grany ones) and rubb off the contact of your RAm.
EVEN IF it doesnt seem dirty - just rub them thoroughly.
Also, dab the brush with some alchohol, and clean the RAM slot again, and then the RAM modules.
(everything should be dry by the hours-long power drain)
also - remember to make sure that all the other new parts that you're carring in to test. ARE IN FACT (try them AGAIN).. fully functional.
trouble shooting doesnt help when you tools are dead
good luck man.