Why my laptop is not working not turing on only chagering light on

Your laptop is receiving power as indicated by the charging light. Therefore, the power outlet, your adapter, the cable, and the charging circuit in the laptop are functional.

If you press the power button and hear or see nothing on the screen or any LEDs other than the charging LED, then the problem in internal to the laptop. It could be the power switch or associated circuit. Sometimes that circuitry is on a separate PCB. That makes life and wallet a lot easier. If it is on the motherboard, then it may be economically not fixable.

If it has an HDD you should be able to hear it start up. The fans may not initially run fast enough to hear. You should also see something on the screen. In a dark room, the screen will show some light. The HDD activity LED should also be blinking. If none of that is evident, then it is the power switch OR a CPU/motherboard failure.

Given the copy paste AI answer and lack of updates, I've seen this before with HP machines. It depends on the type of battery you have and how you solve it. Most of the time, it's due to battery resistance causing the boot issue, and sometimes a corrupted CMOS RAM. On machines like the older Pavilion 15s, such as the 15-x series, where the battery can be removed (for example, the HP VI04 3C pack), removing the battery and simply plugging it into power does the trick in many cases. Not always, but it was always the first thing to try. If it continues to happen with the battery after this, it is often a sign that the pack is faulty.

The ones with sealed batteries which require bottom panel access are trickier, but it still works - the main difference is you need to dismantle the laptop and either fully remove it temporarily (as is the case in some EliteBooks like the 640/645 due to the wire being too short to just disconnect), then holding the power button and then just running the computer on the adapter - once it comes back up to the HP screen the trick is to press ESC to interrupt the startup. Shut it down at this point, unplug it and reinstall the pack, and see if it continues - if it does, you have a bad battery.

If this doesn't work, pull the CMOS battery. Some are easier than others, such as the EliteBook and later models like the 15-ab where it's accessed from the bottom and done in 5 minutes, but the 15-p and some others, like a lot of the legacy Compaq models HP used to put reject parts like Celerons in until killing Compaq off, require motherboard removal. HP and the others basically all use ponytail style connectors on their batteries (HP loves these on the Pro/EliteBook), while consumer models have a socket you remove it with a pry tool or flathead screwdriver on the metal tab. You MAY have the problematic machine which requires motherboard removal based on the battery type unless HP put it under the HD cover :-(. HP has the SM here: https://www.hp.com/ctg/Manual/c03762978.... -- it's the same as the CQ45 as HP rebranded the CQ45 once they discontinued the Compaq nameplate. Yours doesn't have the bastard chassis where you have to take the motherboard out, which was super rare in that era because they sealed it in the CQ56 such the MOTHERBOARD had to come out.