I just installed Ubuntu 11.10 on a friends Dell Inspiron laptop. I normally boots up to Windows Vista Home Edition. As part of the install procedure I reduced the size of the largest ntfs partition to allow space for an ext4 root partition and a small swap partition. After the install completed it prompted to restart and what followed was a reboot with Windows coming back up without any multiboot menu screen. Where is the grub boot menu?
You'll need to install GRUB manually. To do that you'll have to boot up using a live CD then do the following: