My PC power button was poured with water now the screen doesn't displa

@mvelimhlongo you most certainly have more issues than a damaged power button. I imagine that you have way more power damage and may have shorted out the power board/circuit. It's time to disassemble your computer and to take a look at what is going on there. You will need to check for corrosion and shorted components.

Use this HP Compaq Presario CQ57 Maintenance And Service Manual to work on the disassembly. Once disassembled and the motherboard etc removed, clean those with +90 isopropyl alcohol to clean whatever water damage may have occurred. Use something like this guide Repairing iPhone Liquid Damage for the cleaning. Yes, it was written for an iPhone but the steps for the cleaning of your boards are the same.

Next do a visual inspection and check for anything odd looking. You can always post some good pictures of both sides of your boards with your Question. That way we can see what you see. After that, you do want to check your power circuitry. Use the HP Compaq Presario CQ43 CQ57 Schematic for that. Again, if this is new or to daunting task for you, let us know. We can always try and help you out. Adding images to an existing question