My friend bought this used laptop that was working on battery only and had a bad HDD. I purchased a new AC jack cable harness and installed it. I installed a new HDD. Everything worked fine. I installed Windows 7 and all the updates and reinstalled all of his data. It ran fine for a few days. I gave it back to him and it won't power on at all. No lights, no beeps, nada. I have checked the power supply and an alternate but it won't power at all. I have tried with and without battery with no change. There was a small area on I think the ground wire from the wire harness that I installed that initially when the retaining clip, metal, touched the wire the power supply beeped and told me there was a short. I covered the area with electrical tape and it worked fine. I am confused. I don't know if it is a bad CPU or motherboard or what not. Any suggestions to narrow it down?
P.S. I installed a second new ac wire harness thinking the initial one failed and the second one made no difference. It still has no life. Worked fine the night before died in it's sleep. LOL.