Question : Problem: Noise at computer boot

Since yesterday when I boot my computer, I can hear strange noises ..."Tac tac tac" around 20 times, that lasts around 10 second as I can see the boot screen, so really during the first 30 seconds. Then the sounds stop while computer carries on its windows startup in a normal way. I can't really say these "tacs" come from the HDD, maybe more the motherboard while trying to check sth. These noises are NOT the beeps that you could hear when sth is going wrong. Also, after the boot, the HDD does not seem to generate strange sounds at all. I can hear it working like normal. Any idea? What should I do to figure out what these noises are and fix them?

Answer : Problem: Noise at computer boot

Could be a fan bearing in the CPU heatsink fan or PSU fan.  Possibly even the hard disk.

Disconnect the hard disk and insert a bootable CD in the CDROM drive and boot.  Have the sounds gone?  If they have start looking at the hard disk.