I had bought a laptop HP PAVILION dv9350ea, is still on guarantee. Last night when he was on the stend by I just try to turn on, whole screen was black and he did not turn on. It was nothing that we can do about it. We just turn off the laptop and try agen to turn on, but nothing has change the screen was still black. Until now one I can not turn on my laptop?

I'am afraid you have a motherboard problem, HP is well known for this, the only option is replace the main board, there is no other way.

Check for loose cables, I suggest unplugging them and replug them back in just to make sure. If the problem continues, the LCD would be faulty than.

Try to connect to an external monitor and see if this give an image. If it does, then the Inverter / backlight or possibly the VDU cable on your laptop is damaged.
If it does not, the issue is most likely a failed graphics chip (common on these models). You CAN get the chip "reballed" but this will cost about £70.00, and not guaranteed to last

From what you have specifically said here, It sounds like your graphics car in the HP has failed. This is a very costly service to replace thru HP. Although not necessarily guaranteed, an authorized reseller may be able to fix it for less, but at this point you are better off selling it as broken.

Turn off the Notebook remve all the peripherials, Remove battery and disconnect AC Adapter and then press and hold down power button for thirty seconds.
After 30 Seconds connect Battery and Power supply as soon as you tun on the Notebook keep on hitting F10 Notebook will show BIOS then F9 Notebook will show Load Set-up Default than Hit yes and Hit F10 again it will show save Exit and chnages now that show Fix the Problem

Thanks and Regards
Neeraj Sharma
HP and Compaq Notebooks Expert

Unplug the unit, and remove the battery. This will shut the machine off completely. You do not need to let the battery die out. Then power the unit on again. If the issue is gone, consider turning off hibernation ( power options inside control panel)

sounds like you bought a bunk battery

This problem make me think of the defect on the AMD models. Check this link http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01087277&lc=en&cc=us#, it might be covered free.

I had this exact problem with a customers computer andi found out that HP put faulty motherboards in the DV6000, DV9000, Compaq V6000 Series Computers. Thankfully HP fixing all computers for free and extending the warranty even if the warranty has expired they will ship you a box and you ship it off and they fix it at no cost. the turn around period is about 7 days.

Here is a link to an article that talks about it
http://mattsblog.ca/2007/12/14/having-problems-with-your-hp-pavilion-dv6000-dv9000-or-presario-v6000-series-notebook/

Hope this helps!
NosirromNet

the ac adapter needs to be pluged in, try the normal mode..
its hard to fix it from here, if you could get someone to look at it?