Problems with older Macbook after not being used for long time

Hello everyone!

I have an old Macbook Pro (early 2008) that has got some problems after bieng switched of for 5 month.

It has always worked fine for me, and it worked well when i put it away. But when i tried to start it for the first time in about 5 mouths, nothing happened.

The problems I have is:

It only starts if I hold down the power button a few seconds and then plug the power supply in, keep pressing the button a few seconds after inserting the supply, release the button and then press it again normally. It then starts. Took some time to find this way starting it.

The fans are always on max RPM ,so it's a very noisy. It's not hot or full of dirt at all.

The battery isn't charging,

the power supply LED is green, but the battery is completely dead (the green lights on the battery don't even flash). A strange thing is also that the computer cannot be switched on when the power supply LED is green.

When started, the battery symbol has a cross over it, and is says "no battery available".

The keyboard light is off, except for the green Caps lock light.

Nothning happens when i fold down the display (it should get into sleep mode)

I have tried resetting the SMC, but with no difference. Alaso tried updating the mac software.

Anyone got a solution?

Thank You