Before installation, I had a dual-boot menu (XP and Win 7, both 32-bits). I installed Ubuntu 12.04 and when I boot the system, I still see my both OS but not Ubuntu.
HD devices are followings:
160 Gb HDD with XP system, 7 system and data partition
1 TB HDD with unused NTFS, data partition and Ubuntu partitions (/home, /, /boot and swap)