Vostro 1550 - power button & wake from sleep issues.

Hi there Dell community!

Hoping you can help me with a very frustrating power issue on my Vostro 1550.Basically my issue is relating to the laptop not properly shutting down and responding to the power button input. The only way this laptop shuts down is through a force shut down of holding the power button down for 10 seconds. Of course this is not a windows initiated  shutdown so I need to go through the 'recovery' feature every time I boot up the laptop.

If you put the lid down, it'll not shut down or go to sleep despite the settings telling it to.

If it goes to sleep, you will not wake ie up through pushing down the power button, You need to force shut it down again.
I've checked the power management settings and can't see anything unusually different to my other laptops. The shutdown/sleep options are default and it's definitely not set to not shutdown or go to sleep when the lid is closed.
I've also done a full clean reformat of the computer to see if that by chance might help but it hasn't. I'm now wondering if it's a hardware issue or maybe the BIOS needs an update ?
Any ideas on the cause or how to fix?

Laptop is out of warranty but I'm done hardware repairs on laptops in the past so shouldn't have a problem if I need to replace a part.

Do really appreciate any and every help. Thanks!