Sony Vaio Fit 15A no power

[Speedy cd]

My Sony Vaio is not turning on or charging what so ever. I've replaced the battery but to no avail. Pressing/Holding the battery reset button as well as the assist button doesn't do anything. My A/C Adapter seems to be functioning, however whenever I unplug it, the green light on it sticks on for a minute before fading away; not sure if that's normal. I'm thinking it could be the motherboard. When I opened up my laptop, there was barely any dust inside it. Any possible solutions I should try before going to a repair shop?

 

[Laptop_Nerd]

Hi,

Please do try these troubleshooting steps that may help.
- Start by doing a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds then try booting it up again.
- If this will not work, do test the AC adapter if it's working properly. Remove the battery and power the laptop with just the AC adapter connected and see if it will boot up or not. do also try a different AC adapter that has the same voltage and see if it will work or not.
- Proceed with reseating the RAM's if trying a different AC adapter will not work, remove them all for couple of seconds then put them back in making sure everything is seated properly.
- If it will still not work, connect an external monitor and see if you'll get any display from it. If there's a display on the external monitor that could mean that the problem is the built in display.
- But if there's still no display on the external monitor that means the problem lies in the motherboard.