I am not sure what is the exact cause so pardon me if I post in the wrong section.
Recently I upgrade my graphic card from the integrated GeForce9100 to GeForce GT240 GDDR5. The game performances are significantly better with the new graphic card but another problem occurs.
When I play Call of Duty 2, if I pause and jump back to the windows a buzzing sound from the computer case immediately follows. The same problem occurs when I close the game application, there will always buzzing sound coming from my computer case. The sound disappears in approximately 1 minute and does not seem to occur until I close another game application.
I suspect that the sound is from the PSU (if I press my hand on the computer the buzzing will disappear, but occurs when I lift my hand), but I am not exactly sure what is the cause and why.
Hope someone can help me with this problem and direct me to investigate the cause.