As with the others, grub recognized my other OS (windows XP professional) when I installed 6.0.0 squeeze (stable) i386 I downloaded, but when I booted only Linux (& Linux safe mode) were listed and would boot.
I have two hard drives: listed as *sda* I have windows on (and did not change it's partition table), and a bare new hard drive listed as *sdb* is where I partitioned/formatted using guided partitioning with LVM's third option (home, root, swap, temp, usr) and installed Debian. I only installed the defined collections "Graphical desktop environment" & "standard utilities". It was strange when Debian listed the two hard drives as SCSI1 (sda), and SCSI3 (sdb). My system has only IDE channels: IDE channel 0 Master - old HD with windows, IDE channel 1 Master- DVD drive, & IDE channel 2 Master- the new HD (SATA drive connection). Others have said they corrected the GRUB problem by "running update-grub". How do I do that? When I tried "update-grub" I got a "on such command" message. Stan.