I just succesfully implementing dual boot Windows 7 and Ubuntu Jaunty, using Windows 7 Bootloader, with the help of awesome application called EasyBCD. My first trial was using GRUB Bootloader (install to MBR), with the result "BOOTMGR is missing". Apparently my GRUB installation on MBR, not just failed, but also destroyed Windows 7 Bootloader.

Here is my disk partition mapping, my harddisk size is 80GB:

# Primary partition
/dev/sda1 100mb - automatically created with Windows 7 installation
/dev/sda2 32gb - Windows 7 installation

# Logical partition - Ubuntu
/dev/sda5 100mb - boot
/dev/sda6 2gb - swap
/dev/sda7 10gb - root
/dev/sda8 32gb - home

Before installing Windows, I move the GRUB installation from MBR to my root partition. This way, I can switch between Windows 7 bootloader and GRUB bootloader.

After installing Windows 7, download and install EasyBCD, run it, then go to add/remove Entries:


In Drive, choose your root partition, click 'Add Entry' button, then Save. That's it! Restart your computer, and you'll get Bootloader to choose your Operating System :)