@Nitra1
If the device you left plugged in drained the battery so that it now, will not start the laptop, if it does not start plugged into the wall, then you will not be able to run diagnostics to find out what is wrong with it.
If it is NOT possible to run diagnostics, then there is NOTHING more you can do by yourself -- and there is NOTHING we can do.
You will need to have the PC physically examined in a service facility by folks that can run their own diagnostics to determine what is wrong with it. And the problem with that is, while HP does do repair work of some sorts on PCs still under warranty, they generally do NOT do repair work on PCs out of warranty because they are not a general purpose repair facility. You would have to contact them in advance to see (1) if they are willing to work on it, and (2) if they will provide you any kind of repair cost estimate.
Since 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 that link does not get you a useful page, then use the main HP link:
http://www8.hp.com/us/en/contact-hp/ww-contact-us.html
If you can't get assistance from HP, then you will have to seek out a local laptop service facility to have them examine it for you.
Good Luck
I am a volunteer and I do not work for, nor represent, HP