I really need your help, my Sony Vaio laptop (Y series, VPCYB15AG) has a black screen. I turned it on, the power light was on, I heard the fan, but nothing else happened. The screen didn't display anything. I tried the removing battery trick where you hold the power down for 30-60 secs but it didn't work. I also tried to connect it to my TV via HDMI but it didn't show anything (my tv tried to connect to my laptop but then it showed 'no signal') I don't know what to do now.
The problem you have might be due to the video chip on the motherboard. Sometimes, after much of a use and little cooling the North Bridge desolders itself and "paste" is being removed, therefore the screen doesnot turn on and there is no video signal at all. If you understand the notebooks hardware you can fix it yourself by opening the laptop and see if the chipset that is next to the processor is unsoldered, otherwise you can take it to a technician to get it soldered again.