Sony VAIO Laptop Power Up problem

Having problem Powering On an Old sony Vaio PCG 954A or (PCG FX 140) When I press the power Button all the little power light buttons turn on for a SPLIT Second INCLUDING the FAN but it does NOT Power on all the way, if I keep pressing the power button it keeps doing the same thing over and over. Afther a few try’s it TURNS on and laptop works perfectly. Lately it does not turn on afther a few try’s anymore. But afther a few day’s have passed I will try it and it will turn on on the first try and it will work great once it is powered on, and it can stay on 24/7 without a problem. The MAIN PROBLEM is powering Up the Laptop, have tried starting it with power supply and only with Battery power and does the same thing. Tried troubleshooting but it say’s that all components are working properly. Lately havent been able to succesfuly turn it on anymore but still geting the same reaction. Can U help pointing me in the right direction to troubleshoot? Thank you for your time