Dear All I had two x86 platform that I needed to install CentOS 5 on them. On one of them that had Windows OS pre-installed, I installed VBox and then I installed CentOS inside its VBox. On the second platform, I tried for a fresh installation of CentOS as its primary OS (I mean inserting the CentOS installation CD and rebooting the machine and following the instructions to install the CentOS). On the second platform, I want to install Windows OS again and as I don't find proper VM machine for my CentOS so I tried to put the Windows installation CD and reboot the machine but it was unsuccessful. Actually it didn't read the Windows installtion CD and just boots up from its CentOS . As I chose to 'remove all partitions on this machine' when installing the CentOS so I think I need to change its FAT to be able to re-install Windows OS. Can you please comment me back what was wrong on my second machine that I cannot re-install Windows OS on it? Thank you