wierd sound from case

[mindwip]

hi all

real simple here is my problem, there is a sound (sounds like a bad bearing)
that comes and goes, often i will not here it for days then one day it might do it all day, it likes to do it on start up then when my os loads it stops

it is not my hard drives,
it is not my lan sound grapghs cards becuase they have no moving parts,
i just replaced my power supply and that did not work
i am 98% sure that it is not my cd roms

the only thing left is my cpu fan(right)

just like to know if any one else has a beter idea of what it is,

ps, if you need more info i will try to answer it

[mindwip]

i forgot when i um gentley tap the back of the case (near power supply) it goes away

the sound is also never constint, it changes volume and pitch when is fussing about

[sdousley]

does sound like some sort of fan.

Have you gor any other CPU/Case fans u could check it with?or take the CPU fan out and plug it onto another computer.