Strange sound from my pc

[carpenter20m]

Hi, all.

Lately, I can hear this strange sound coming from my PC. It sounds exactly like the one, when it finally turns off...you know that last sound, when power is cut.

Does anyone have any ideas about what it can be? It kind of worries me, even though I haven't seen any performance alterations.

For the record my system is this:
CPU: E6400 OCed @2.56 GHZ
GPU: Ati 4850
Mobo: Asus P5B (P965 chipset)
WD HDD 250 GB
2 GB RAM Transcend PC2-5300
Corsair 450W PSU

So, should I be worried?

 

[GhislainG]

Can you determine where it comes from? It could be many things, but being to identify if it comes from a fan (block it with your finger to temporarily stop it), the PSU or something else would help.

 

[carpenter20m]

Thanks for your answer. It isn't a constant sound. It may happen now and never happen again within the day. It sounds like a big switch being shut down. I can't locate it, if I don't know when it will sound.

So, any ideas?

 

[GhislainG]

It's difficult to analyze an issue based on the description of a sound. It could be the PSU, a fan, etc. Do you have case fans? If so, I would disconnect them one at a time to rule out that possibility. It can't be the CPU or memory and most likely it isn't the motherboard.