I have an extra harddisk. I install newer operating system on it. I installed Ubuntu, Linux Mint, Peppermint one, Peppermint Ice, Lubuntu, Kubuntu, Open Suse, Fedora and Dream Linux on it. Today at afternoon I have install PCLOS Gnome on this harddisk. But alas. When I restart my machine, I astonised to see that all OS has gone from grub menu.
What a bad luck. I know PC Linux OS won't take any liability for it. But, I am sure that it is done by pclinuxos. No other operating system have not done this kind of odd job before. I don't know why pclinux os delete others from grub list.