no beeps? sounds like you have been reseating some contacts to get it to work. heat will build up varnish on componet contacts. I would suggest doing what you have done before to get it going but use a can of contact cleaner. be sure to let it dry before assembly. then download and run this
http://pc-wizard-2008.en.softonic.com/
report your voltage,temps,and fan speeds. also, I do not reccomend leaving your pc on because nowadays pc's keep voltage going to your mainboard anyway.