Yeah after installation of Windows seven – my Grub-Bootloader was removed and I get only the Windows bootmager.
This article describe hot to mount root “/” which was created on LVM from a live CD and install GRUB Boot-Loader.
Step 1: Get a live CD in my case it was Ubuntu 10.10 Desktop edition.
Step 2: Boot from live CD and get your network to work, you will need it to install some packages.
Step 3: Install LVM to mound root
apt-get install lvm2
Run pvscan to scan all disks for physical volume:
Run vgscan to scan disks for volume groups:
Step 6: Activate volume groups:
vgchange -a y
Step 7: Run lvscan to scan all disks for logical volume.
Step 8: Mount your root or another devices:
mount /dev/VolGroup0/root /mnt/
For GRUB installation refer to this article