Hi, I tried this option "linux acpi=off pci=nommconf" as well but the problem is when I use this I can install the OS but when try to boot on to the OS it's hang up on the boot up progress bar screen of the CentOS and I can't do any thing. So I checked it with the text mode loader it was the same problem can any one help me to over come this. Thank you -- Sadaruwan Samaraweera