Clicking noise

[d3moliti0n]

Hi

Whenever I start up my PC, after the initial screens (the ones that let you into the BIOS) and just before the Windows XP loading screen, there is a clicking noise coming from my computer tower (which lasts about 20 seconds or so) and it sounds like it is coming from the front of the computer where the hard drives are located. The thing is, I have checked my hard drive's several times for errors, scanning them and checking the health etc and there are no problems.

I have also tried unplugging each drive upon start up (I have 2 HDD's), basically leaving one plugged in then starting up the comp then switching around and trying the other, but the clicking is still there even with them unplugged. This has been happening for about 2 or 3 months now I think aswell.

Does anyone have any idea what this noise could be?

Thanks for your help.

 

[d3moliti0n]

The noise stops after like 20 seconds or so, just before the Windows XP loading screen appears.

 

[d3moliti0n]

The only drive's I have installed on the system are a DVD-RW (and it's not coming from that) and the two hard drives, and the noise is like a rapid clicking noise with a 2 or 3 second pause, then it starts up again for another 10 or so seconds at the same pace, and the noise is the same every time I switch on the PC.