Notebook Sony Vaio vgn_fs840_w. The computer won't to start.

It sounds like you may be having a video related issue. These issues may indicate that you have a problem with either your video card or your lcd screen. To isolate the issue, you have to connect an external monitor to the VGA port of the portable system. There should be an S2 button on your laptop which should allow you to switch videos. Press that and if the video appears on the monitor, then it is an issue with the LCD screen. If nothing happens, you have a video card failure. These are due for replacement already.

you need a converter to convert the VGA analog to HDMI digital signal

it should be in the front of the laptop the very front.A series of lights and symbols should be above it look below the symbols.

check insert the battery and plugin power cord, press power button and if still no power, please bring it to sony service center

Did you accidentally push the Function + (whatever) keys that switch the video out to an external monitor screen?

If the backlight of the LCD screen went bad - you could turn off all the lights - need a very dark room - you could still see the contents of the screen.

turn on with battery if boot there problem is on the jack.
reset the bios battery .
check if u cut the mainboard during changing the jack.

check two things, video (reinstall drivers) and the other may be a heat event, look in the BIOS set up in the event log.
blow dust out with compress gas especially around the heat port and exhaust fans.

http://mark.rehorst.com/Sony_Vaio/index.htm

Need VGA Drivers for sony vgn fs840/w

turn it upside down and pat it a little or use some air from a canwith it upside down

I’m happy to assist further over the phone at https://www.6ya.com/expert/james_1cb31da1bc8c6102