u should un plug everything when u fiddle with things just for reference.
do you get any beeps? if so what kind
do u have an extra memory stick that you can replace your other one with (just to see if its your memory that is causing this problem)
i had a similar problem, and it was caused by bad memory. basically my mem stick was fried (i dont know how it got fried) but when i took a different memory stick and replaced it everything worked.
so maybe thats your problem