Acer Aspire 571 G is getting no power?

Re
- in Acer
6

About 3 years ago I got my laptop called Acer Aspire 571 g in the spokes of my bike. The logical consequence is Screen Broken. Then I used the PC until the newly ordered screen was there, then I took the PC and the screen to a friend who left it for about 3 years and nothing against now I got it back yesterday after nothing happened and repaired it himself only now it does not start.

He does not get any power from the fully charged new battery (the old one had expired in the meantime) and he gets just as little power via the power supply unit (since there's also rust all over during this time) I cleaned the opening and I tried many power packs none worked what can I do now that it may run again

As

Can you open it and check for damage to the cables and / or the circuit board?

Re

I've already done that inside, everything's fine. There's electricity coming through. Do you have any other ideas?

As

Hm, it was without power for a relatively long time, with some mainboards the start no longer works without a charged bios / cmos battery, this may have been discharged in the meantime. That can be the case here, but I don't know exactly because I don't know the mainboard of the laptop.

Re

Yes that can be but the lamp that shows whether the battery is full or is being charged should still be on, right? Because it's over

As

Is it achieved via the mainboard? Then rather not.

Re

Okay then I'll have a look tomorrow and get back to you, thank you