Thank you for your replies!^^ I download drivers only from manufacturer website. I already check 1.84 to 1.86 driver update via inf file, always the same, computer reboot. I always have a 0x0000007E error on HDAudio.sys. So, method tested: Fresh install with sp2b cd, chipset install ok, audio install reboot Fresh install with nlited xp (with 1.86): Install freeze at install drivers procedure. Fresh install with R1.84: everything is fine, update with R1.86 (both inf and installer): reboot Bios was updated on several mobo and the same symptoms occured. I build computers for my work, so every parts are brand new and different (lot of asrock mobo ^^')