I came across this problem today while trying to help a client out. I thought it may be a simple re-seat of the processor as I had run into something like this just a few days ago with another Sony laptop. However, this wasn’t the case. I tried removing the processor, re-seating it, removing the memory, removing pretty much anything that didn’t need to be installed in order for the computer to run.
I still could not get it to turn on. I sat there for a few seconds, thinking what could be causing this. I fired up my trusty ole web browser, IE7, typed into Google, “VGN-S150 no boot.” The very first link brought me to one page that made mention that there is a defect within the video unit on several Sony models.
More searching brought me to another website in which there were multiple complaints regarding no boot problems or video display errors. One person linked to Sony’s actual website. On that page, it goes on to describe that there is a defect with these certain models and that like I mentioned earlier on, that they are taking responsibility, depending on how long ago you purchased it and if you can furnish an actual sales receipt then you may be eligible for a free motherboard replacement.
Well, good luck!