Q: Why doesn't my eMAC respond to me when it does to my son?

Haven't noticed any unusual pressure needed on my eMacs.

Might be time to replace the PRAM Battery, 4 years is close to their lifespan, far less if ever without AC power, & can cause strange startup problems...

http://eshop.macsales.com/item/Newer%20Technology/BAA36VPRAM/ 

You may have to, but I'd try it without that first, no need to put the bottom cover back on to give it a try.

Oh, just remembered, some G4 towers had a problem with the start button, where they needed to be pressed off center, a corner of the button so to speak... not heard of that on eMacs, but...