high load php-cgi?

[shico]

hi,
i have centos 5.3 server with ispcp ,
the server is very slow ,2.75 GB memory used (have 4 GB total)..
when i am using the command top in centos i see a lot of php-cgi services running and a lot httpd services too...
more about installation ispcp the dns is not working and the incoming email...
i had a lot of problem installing the ispcp (proftpd,and smtp) but i manage to fix them,but the memory is out of my hand and so the dns and incoming emails.
i check and reviewed the msgs here on the forum and at google but i didnt found any help...

p.s.
i am a newbie at centos... and i need help if possible