So i was going to put together my computer that i just got all the parts for and i went into my dell. I just looked around to see what computers looked like inside and all that stuff so i just unplugged the floppy and w/e put it right back together. I unplugged some things from the mobo but put everything back. I closed the case and hit ON but the computer turns on and off immediatly. A little green light in the mobo goes o and then the fan gives one revolution but then everything stops. Please help... very sad right now