goady 0 Newbie Poster

Hi I'm new here and would be grateful for some advice. I have an Advent 9617 laptop. The DC power cord shorted out and was replaced along with the charger. The new charger works fine but laptop would not run so figured out it was probably the power jack at fault too. I replaced that and now the battery will charge.
But, the machine will not power up, with or without battery. I've tried the ATX reset several times.
This is what happens- I press the power button and for a second or so it appears as if the machine will start but then all the leds that have just come on instantly go out. I have to disconnect power cord or battery before I can reattempt start up. It did actually boot up once so thought I had cured it but alas no. Should I throw it in the bin?