Q: It doesn't over-heat, or slow down (It did 2 weeks ago, slow down, but its good and running normal speed) Now it just hum's loud, I've been meaning to spray the fan for dust and every-single other place visible, Computer inside (software) runs fine, tad slow on major games but other then that pretty good. If I asked Dell to repair such problem what would I ask them to fix and the problem?
A: get close to you case and see where the sound is coming from. probably a case fan (easy to replace), your PSU fan (you'd need to replace the whole psu), or you processor fan (not hard to replace but you dealing with sensitive equipment). If its comming from a hard drive, back up your important files because it may be a sign that the hard drive is about to go. If you keep the computer in a cooler area it won't have to run fans as hard to keep the system cool.