Administrating a heavy loaded Db Website - Experts Only

We currently have a web site that has extensive MySQL Db operations and it daily exceeds 80,000 Pageviews. But we are experiencing serious outage and slowness every two days and we end up restarting apache and MySQL. The required tasks include the following: 1) We need to have some sort of profiling to locate the source of the problem (MySQL profiling or Apache profiling), in short we need to know which file has the most time consuming code to reduce it. 2) Advise on what MySQL configuration and Db types that should be implemented 3) Advise whether it's better to use Apache or LightHttpd 4) Advise on whether the current setup is sufficient to play flash videos 5) Advise on whether we should migrate to a VPS and split into multiple servers or one dedicated should be sufficient 6) revise server for unwanted process or services Some Symptoms: 1) MySQL CPU utilization jumps insanely from 1% to 80% to 160% then jumps back to 50% then to 2%. 2) Upon server outage CPU load on Cpanel is 0.00 3) service is restored by restarting apache and MySQL Here is some information about the server: Distribution: Linux [login to view URL] [login to view URL] #1 SMP EDT 2008 i686 athlon i386 GNU/Linux #Distro: [login to view URL] #PHP: 5.2.8 #MySQL: Ver 14.12 Distrib 5.0.81, for pc-linux-gnu (i686) using readline 5.1 #Server version: Apache/2.0.63 #Cpanel::Easy::Apache v3.2.0 rev4561 #PHP Modules: bcmath calendar ctype date dom ffmpeg filter ftp gd hash iconv imap json libxml mysql pcre posix Reflection session SimpleXML sockets SPL SQLite standard tokenizer xml xmlreader xmlwriter zlib #we are extensively using "mod rewrite" We need to someone that can educate us and help us deliver a better service to our clients Thank you.