Hello!
There are several things I would like to know about your project:
1. What's the server configuration (RAM / CPU of interest for me)
2. Was the server ever tuned/optimized in any way after it was installed? Anyone else done any apache, php, mysql config tweaks?
3. How many domains do you have on your server? Do you have any idea about which one of them is most likely to cause the issue, eg, based on the traffic reports? How many databases, and how large are they? And what php platforms are there used on those domains?
4. Do you see any errors in the mysql log and/or in the slow query log? Are they at least enabled?
5. How often do you get the server frozen? Do you need to reboot it when it gets stuck/unresponsive?
Regards,
Dragos