lol, heat after all of this !
we should have asked you about that earlier tbh, its easy to overlook the things you check without thinking :s
its an easy problem to fix tho
depends how you want to do it, I say, if your going to do it you may as well do it right
Is swap that back fan for a 120mil fan instead
the front too if itll fit#
tidy up the wireing for better airflow
new heat sink and fan
than you should be sorted