Over the last year we've had issues where our RH9 server has been using up memory, to the point where I have to do scheduled reboots every few days to keep it from crashing and having to open a reboot ticket.

The server load also seems to run in the 'red' throughout the day (usually between 1 and

. I've had a someone come in to 'optimize' the server, but that didn't do any good. Actually, after they put in all the newer antivirus/antispam/etc. tools i think it's worse off. From reading the forums, theres the possibility it could be a mysql issue, but I'm not really sure where to look. Anyone have any ideas?
It's a pretty low end server (celeron 2.4 w/ 512 memory) however only runs about a dozen minimal traffic sites. We've had the server for about 4 years, so perhaps it's having some type of hardware failure.
Is it even worth trying to fix, any ideas would be helpful. Should we just replace the server? if so, can someone point us to (i'm sure there are plenty of posts) the best way to replace a server with minimal amount of downtime. I'm not exactly sure if there is a howto on that and if there is an easy way to transfer websites and settings over to another server.
Thanks!