Ok, I have never experienced any problems as such in multiboot.
On the first partition I have win 7 followed by Sabayon.
It was booting ok into Grub.
Now I attached a second HD and installed win 7 only for games for my kid.
Now grub is not booting but it always starts the win7 bootmanager
I checked the bios at least 10 times but it is set correctly to boot the first HD with grub but it only boots the win7 bootmanager.
Easybcd brought no solution, it starts grub but with error.
Already tried reinstalling grub with the sabayon dvd but first time nothing happened and from the second time I tried to use the dvd to fix it always crashes.
Anyone has a clue what this is causing, thanks for helping me out.