Well its best if you get aftermarket cooling for ur computer, seeing as how stock your stock CPU fan is not good enough(it only cools at its regulated clock speed, any higher could cause more heat in your computer then there should be) and may cause something to not work. Definately recommend you to get a new CPU fan . And 1 case fan isn't enough either, if you have another case fan slot open , put another one on. If you want to check your heat teamp of your CPU and MOBO, use Motherboard Moniter. And use Prime 95(let your computer on for 24 hours) this program stresses your computer by searching prime numbers.
Its good to check for stability on your computer, if it can last for 15 hours(at least) after your overclocking, your computer is pretty much stable.