Excuse me, could you be more specific about what you did?
Do you have MBR or GPT installation? Is your FAT32 partition meant for backup of Windows, or it is EFI's EFI System Partition?
Did you use graphical installer of Mint to install to HDD? You made the partitions on HDD with GParted and told it to install GRUB? (GNU Parted <1.7.1 is known to remove first-stage bootloader from MBR in case of EFI/GPT scheme: http://www.rodsbooks.com/gdisk/booting.html)
Did you install GRUB-legacy or GRUB2? Assuming, you're using MBR scheme, did you install its 1,5-stage in case of GRUB-legacy, second-stage in case of GRUB2 in DOS-compatibility area/MBR-gap (31.5 kb between MBR and first partition) or right in filesystem? Consider related problems here: http://www.gnu.org/software/grub/manual/grub.html#BIOS-installation.
When did you install Windows on SSD? Before Linux or after that? Did Windows see or use HDD upon installation? (I'm asking, cause Windows is known to be harsh to other OSes, if installed second).
If you're no House M.D. and not obsessed with finding out the reason, but just want to solve the problem, in case of MBR scheme you could boot from Mint LiveCD/LiveUSB, mounted your HDD's ext4 partition to /mnt/sda1 (I suppose, it contains the root filesystem) and installed grub again with something like
sudo grub-install --root-directory=/mnt/sda1 /dev/sda, where /dev/sda is your HDD device file. :)