Sony VGC JS320 fails on start up, screen goes black

I am working on an All In One Desktop JS320 running Vista Home Premium 64 bit that recently went out of warranty (of Course ). It starts to power on, can see the Viao splash screen and the Windows start up. Usually before it even gets to the desktop, the screen goes black. The hard drive light had continued to run as if it were still 'working' and power would stay on until a hard shut down was done. Now after changing the motherboard, when the screen goes black, the machine shuts down. This is happening in less than a minute.

If I go into the BIOS, the same thing happens so I have very little time to look at any settings, but I didn't see anything that I could change that might help.

I have removed the memory, changed slots, a new motherboad and processor have been installed, tried a different power supply/cord, disconnected the hard drive but this symptom continues on start up. Fans seem to be working fine, they have not been changed. Can't think of what else to change.

In looking for some solution to this there was mention of the inverter being bad, but now that it is shutting down completely, I'm not sure that is the problem. The screen goes completely black, there is not any faint picture on the screen.

Hopefully I've provided enough information. Wondered if anyone had experienced this and what solved the problem.
Thanks for any help.

Hi lcander,

From what i have read, have you ever tested your hard drive?
Can you name the wattage of both the power supply you have tested with?

Thanks for a response.
When I first started working on this machine, the person needed the data from the hard drive so I removed it to another machine and used Knoppix Live to retrieve the material she needed for her work. I also saved the pictures and music she had. There was no issue getting the data.

I have tried a different hard drive in the machine but had similar results with it shutting down. I may see a message about starting Windows Vista. I have not tried any specific test on it. What would you recommend? I would imagine I would have to run it with it connected to another machine since it is now shutting down so quickly.

I can add that I have tried some additional things. Removed memory completely and started it. Nothing showed on the screen,not even the Viao splash, but the machine remained on until I did a hard shutdown. No Hard Drive activity light. When I replaced the memory it would sometimes do the same thing. Even tried replacing just one stick at a time (it has 3GB of mem.) I tried that memory in my laptop and it worked fine, was recognized as 3GB. Took the memory from my laptop, which had no issues, and put in the all-in-one and same problem with shut down or machine would remain on but nothing would show on the screen.

I removed the battery from the system board and replaced it. Problem continued

Occassionally when replacing or switching memory slots a CPU fan error message would come up, tell me to press F2 and I had 10 sec. til shutdown. If I was fast enough to get to the hardware tab of the BIOS it would show fan speed as 0 rpm even though they were running normally. After moving memory around or disconnecting and reconnecting the HDD, it may start up again with the splash screen and can get into the BIOS. Again if I'm quick enough and can get to the hardware tab it will show an actual number of the fan speed.

Anything else I could try???
Thanks

Sorry forgot to respond about the power supply.
It is a 19.5V Sony AC power adapter.
Is there another power supply in the machine itself as in a regular desktop?

you have a bad screen , try to use an external monitor, if everything looks normal in the external monitor then you have to replace the laptop screen.

Thanks for responding to this thread. I really didn't think it was a screen issue since when it would display the Viao splash screen, BIOS screen and when it would occassionally get to the point of loading the desktop, the picture was clear and showed fine. Even the error message about the fan was clearly readable. It would then go black.
Also, this is not a laptop but an All-In-One desktop (although it would have a built in screen similar to a lap top). I don't have a way that I can see to hook it to an external monitor or I would have checked that.
In showing the symptoms to another tech person that does repair on warranty work, he too was puzzled since so many things had been tried to fix this--new motherboad, new CPU, new power supply/cord, switching memory, different hard drive, etc---and still nothing was working. I talked about the screen with him and he too felt the screen was ok since it did display fine for a while.
Would that be indicitave of a bad screen for it to display for a while and then go blank? Is there any other way to test it (I don't have lots of equipment) before I spent $$$ on a new screen?
Thaks

Have you tried the flashlight test?
Do this; turn it on and let it finish, grab a flashlight and point it directly to the screen if you see your desktop (windows i guess) then you have a bad screen.
usually every screen have florescent lamps on the sides or top depending on the manufacturer and the symptoms that you describe are consistent with bad lamps, they can operate normally anywhere from 2 to 3 seconds to a few minutes and then the screen goes black, the best thing to do is to replace the entire screen.
If you can not see anything then there is probably a bad graphics card if your system has a separate one, good luck

Didn't know about 'the flashlight test'. Learned something new. Thanks for the info. Not sure what you meant by 'let it finish'. Perhaps after the splash screen was shown ??? Or something else???
There is no separate graphics card (at least that I could find ), I believe it's integrated on the mobo and that was replaced with a new one.
I'll give the 'flashligt test' a try
Thanks again

"Let it finish" I meant let the computer finish normal boot cycle,
now you mentioned that your computer is shutting down completely,
is this correct?
was this happening before the motherboard change?
is this a new motherboard, refurbish or used?
in any case, you may have a defective motherboard.

Yes, the machine will shut down completely--most of the time. If I disconnect the hard drive it will remain on until I power it off but nothing is displayed on the screen--not even the splash screen. It has been quite a long time since the motherboard was changed out and I can't remember for sure if it would shut down, but I think it did after I switched memory.
A new motherboard was used as the replacement. I have tried to do some searching to see if these motherboards have a history of problems but I can't find much about this model. It's hard to believe that 2 boards in a row would be bad, although I know it's not impossible for that to happen.
Thanks for continuing to try to come up with some ideas. I'm at a loss--and I don't like to let the machines beat me

hi, I have an all-in-one (sony vaio js320)with the same problem as described before.
I just want to know if you fixed yours and if yes, HOW...
thanks