As I recall, most problems with that os boiled down to either extension conflicts or corrupted preference files, or a corrupted pram.

Zapping the pram fixes that problem. It's a boot time key combo. Do it a couple times in a row.

Preferences and extensions each live in a specific directory.

Simply removing all preference files will remove whatever is corrupted . The software will rebuild the preference files as needed. The downside being that you will have to visit all the relevant prefrence dialogs and reset them.

Extension conflicts take more time to resolve.

Also, There is a motherboard battery that may need replacing.