since you didn't mention what things you "messed with" I can't give you any good advice except to find your 'real' power switch. The button on the case usually activates another switch, sometimes via a lever. Sometimes things get a bit out of alignment so the case button never activates the 'real' switch.
But call Dell first before you spend any 'real' money.
I came home yesteday to find the computer off. When I tried to turn it on, nothing happened. As above, there was no noise, no fan activity, no green light -- nothing.
I took off the shell (its a Dell by the way), and noticed a green LCD lights up inside. But nothing else happens.
This also happened when I returned from a week-long trip a few months ago. I messed with some stuff inside, and voila, it worked. No such luck this time.
Do you think this might be an easy fix? It's obviously power-related. Something that Best Buy or Geek Squad can fix, or do I need to go through Dell?
Thanks very much!
P.S. This is my first post!