Help, mt emachine won't boot at all!!

[Butter]

Hi,
My puter won't boot up at all. Nothing, not even the power light will come on, I've changed the power cords, checked inside puter to make sure no lose connection anywhere and everything is fine in that area. But it won't boot, it's dead. Anyone have any suggestion on what this can be, I really don't want to spend unnecessary money trouble shooting to see if power pack, lithum batter...etc..etc......... Was hoping maybe someone can direct me in the right path in where to look to see what is causing this problem or should I pronounce it dead? lol . It's a P3, Running off of XP home. 512 megs of ran. 20 gig HD...It's an Emachine. Anyone have any suggestions for me?? Any and all help would be appreciated.
Thank you,
Butter

[Butter]

Sorry for double posting don't see a edit button, to give you more info on this computer ~ It a 2000 + AMD Athlon processor. Model is T2085. I hope this helps out a little better, I am truely at a loss here. Any and all suggestions welcomed.
Butter

[dvr]

sounds like your power supply. when you plug it in do you hear anything sometimes a fan will start for a split second.