Some Problems - Shall I reinstall the DB?

The 8.x version of PostgreSQL has been installed on my PC for quite few years. It has been problem free until recently. The first problem I have is that a connection can't be established after the PC just starts up although the DB is started. I have to restart it to solve this problem each time after my PC is up.

The other problem, I just find this morning, is that table ID generation. A table ID is defined as the following:

id SERIAL UNIQUE primary key,

When I save a new entry to this table, I get an error as

org.hibernate.id.IdentifierGenerationException: ids for this class must be manually assigned before calling save()

from Hibernate. No all table demonstrate this error.

Shall I reinstall PostgreSQL for resolve those two problem?

Thanks,

- v