When a game starts up with the words "Factory Settings" it means that either:

1. Your batteries are dead.
2. Your battery holder has gone bad
3. The onboard RAM is failing/has failed

A failing RAM chip, as I understand, is very rare, so I'd place my money on your batteries or battery holder are bad. In either case, you should replace the board mounted battery holder with a remotely mounted one, to avoid future potential battery leaking issues from ruining the expensive CPU board. Others recommend changing out your RAM for NVRAM, but that requires sensitive board work that many people may not be comfortable doing themselves.