@Ege Gaming HD,
I don’t know what you’ve tried when you say “I tried every method but it didn't fix it.” but try the following if you haven’t done so already:
Try removing the RTC battery from the motherboard as well as disconnecting the battery (and the charger if connected) and then press the Power On/Off button for a ''full 30 seconds'' to dissipate any residual power from the motherboard to hopefully reset the BIOS back to factory default.
I’m not sure if your model even has one, as the closest [http://h10032.www1.hp.com/ctg/Manual/c05228250.pdf|maintenance and service guide] to your model that I could find was for this [https://support.hp.com/us-en/product/hp-pavilion-15-au100-notebook-pc/12499208/model/12732686/manuals|this] one.
Here’s the Ifixit [guide|100960] guide which may also help.
If there is a RTC (aka CMOS) battery on the motherboard then when it is out measure its voltage. If it is <2.5V DC replace it. Usually they are a CR2032 Lithium non rechargeable and are commonly available. They last about 5 years.
If this doesn’t work then it is a motherboard problem and the schematics would be needed to find out what the problem is.