Server down regularly

[meimi]

Hello,
  Thanks everyone.

Here is the information
FreeBSD 4.8
Server specification:
PIII1.7GHz
512MB ram
80GB harddisk

The server is used for web, mail, dns and databases (mysql and =
postgresql).
Recently, I have recompiled PHP with option curl and openssl added.
The server is in Equinix datacenter and it is not busy, so I don't it =
will
be temperature problems.

Actually, what I want to know is the general steps for finding the =
problems.

Thanks
Meimi