Ok so...

Recently my computer was making some weird electronic humming noises. I brought it to a pc repairtech, and after first a misdiagnose of the problem being the powesupply ( <_< )he said that two of the fans had died out. So he replaced them...

Everything was running fine, but then the computer started to make that same sound again.

1. I turned off the computer and opened one of the side panels.
2. I turned the computer back on so I could see the insides of the computer
3. The computer started with a second with the odd noise, then stopped.
4. Everything is running smoothly now.

Here is the question....

A. Is there something wrong with the casing for my machine?
B. The side panel has air vents...but should I consider investing in a case that has better ventilation?
C. Is there anything else I should be concerned about?

Thank you,

TTC

Check for wires coming into contact with the fan blades. Also check for any dust build up (the tech should have cleaned it) What kind of power supply did he use as a replacement? What kind of computer do you have? Does the noise sound like a Dustbuster or kind of like when you put cards in the spokes of a bicycle?

I ask this because you describe the noise as an electric hum. Are you certain the noise isn't coming through the speakers?