I have a ASUS computer and i'm trying to install ubuntu. I have 2 hard disk, so i installed ubuntu on the second one (where there is no windows 7..), format the partition of 100go in ext4 , and choose at boot sector the partition of the 1st HDD where it was written "windows loader" but had an error so i choose the root of the 1stHDD but still no choice at the boot of the computer, windows boot and no grub... How can i fix it?
It's probably about the boot-order of devices in your BIOS. Check it to put your second hard-disk as the first checked at start-up.
You should try to repair grub : http://doc.ubuntu-fr.org/tutoriel/comment_restaurer_grub
For those who don't speak french : https://help.ubuntu.com/community/RecoveringUbuntuAfterInstallingWindows