So, none of the LED lights are lighting up, i.e. power, HDD lights, etc...? If that is the case, it could be a bad adapter or a bad power jack. You can try removing the battery and then plugging it in to see if does anything. If it powers up, you have a bad battery on your hands.
After a bit of fiddling & switching around Acer adapters with no success I was left scratching my head, so with nothing to lose I thought why not try my Dell adapter I checked the outputs & they matched (nearly) & hey presto the battery charged & the old Acer fired up & came to life.
Seems my Wifes power adapter has developed a fault as well (Which I have now got the blame for & need to replace). The upshot is my Nephew thinks I am great.
The downside is my niece need a new LCD screen which is now my next project, I suppose it bis good Experience anyway.
Thanks buwish for some constructive advice.