Power

[Tarık1]

I press the power key.All lights are on and then goes out.But the device does not  Work.What is this problem

[WAWood]

@Tarık1 

Sorry, but any time a laptop simply refuses to turn on, that tend to indicate a serious hardware failure.

Software failures invariably present with error messages of some kind on the screen, such as No Operating System or No Boot Device. In these cases, reinstalling the OS from media such as DVD or USB fixes the first; rebuilding the boot records using various utilities fixes the second.

There are these interactive diagnostic routines you can run from another PC that will attempt to walk you through some steps to determine the source(s) of the problem: http://hp.dezide.com/ts/start.jsp?guide=NoPowerorBootIssues.net&section=ccweb&as=true&SFS=tdoc

The problem is that we HERE, have no way of diagnosing or repairing hardware problems.

If your PC is still under the original one-year HP warranty, or if you have purchased an extended warranty from HP and this is still valid, then you should contact HP Customer Support to see about having it repaired or replaced under warranty.

If you live in the US or Canada, contact information is on this page: http://www8.hp.com/us/en/contact-hp/phone-assist.html#section1

If you live elsewhere, contact information is on this page: http://www8.hp.com/us/en/contact-hp/ww-contact-us.html

NOTE: After you get through, stay on the line until you are finally able to talk to some one -- it can take a while!
If you have trouble finding a phone number, then try: 1 (800) 474-6836

If your PC is no longer under warranty, you will have to contact an HP Repair or Service Center to see if they can examine the PC to determine the cause(s) of the problems, if it can be repaired, and an estimate of the repair costs.

If you live in the U.S., here is a link to the HP Service Repair Centers:
https://www.service-center-locator.com/hp-hewlett-packard/hp-hewlett-packard-service-center.htm

If you live outside the U.S., here is a link to HP Service Centers, by Country/Region: https://support.hp.com/in-en/service-center

Good Luck