Looking for Computer Hardware Specialist

[Greatguardian]

Sounds like something is blocking your CPU fan from spinning. Keep the case open when you power up and watch the fan to make sure nothing is obstructing it and it is able to spin completely, then make sure to keep cables out of its way when you close the case back up.

Edit: Bad RAM shouldn't cause a loud buzzing. A fan obstruction definitely will.

Edit2: Credential-wise, I'm a computer science major who builds and maintains all of his own computers. I've built and serviced plenty for friends over more than half a decade, and worst case scenario nothing bad is going to happen if you just open up the case and observe the CPU fan. This has happened on one of my machines before, and that loud noise is probably your fan straining to spin against whatever object is blocking it. It's typically just a cable from the power supply that bent the wrong way and ended up smushed against the CPU fan.