One doesnt even boot to bios....Help?

Well bsically, my one will not boot at all, if I press the power button, the power button light comes on, the cpu fan spins up, then stops spins up again, and keeps doing that on off about 5 sec intervals between switching off for half a sec.
Nothing on screen
Power indicator on the left doesn't light up, but does when it's plugged in, so the LED isn't broken.
Checked all connections

Any ideas?
Take it back?
I have added RAM, which I now removed, and slightly screwed the case to make space or a ZIF drive, which isn't installed either.
Do you think PC world will take it back? I'm sure that if I stick the SSD down with double sided tape they won't notice I have ripped out a few screws.
Will they take it back no questions asked? I have had it like 2 and a half weeks.
Will they open it up to check if I fuced it up?
Any advice/help is appreciated!
Thanks
Rory

 

For God's sake, as a mod, I really should folow rule 1, look around or search. lol.
Topic closed for this reason.
I'm in a panic!
Rory