reformat hd and now pc won't turn on??

[Farbio]

so i was reformatting a hd that i was selling, and after finishing, i restarted the pc, it came up to the select which os to use, then i realized i hadn't reconnected my dvd drive so i shut it off, connected the drive and went to turn it back on - nothing, no fan spinning, no psu sounds, nothing.
i have since tried a different psu, checked all the cables from power switches to mb, checked connection of psu to mb, disconnected everything but the mb to the psu and all with the same result - absolutely nothing. anyone have any ideas?

thanks all!

 

[Gurck]

You may have jarred something when taking out the hdd, try reseating everything (ide connectors, ram, etc etc etc)

 

[jm0ris0n]

A motherboard contact could be touching the chasis thereby shorting out your ability to turn the computer on.

Make sure the motherboard is seated properly. Maybe try a different electrical outlet ?