This system is very old! Parts (assembles) are just not hard to find that are even still good.
While it might be possible to fix your logic board the labor costs alone are going to be higher that the value of the system.
Unless you understand the circuit you can’t just assume the capacitors are all bad.
Lastly, the OS this system needs limits what apps will work and lastly its just not safe on the internet from WiFi to web apps.
Its really time to get a new system (used or new)