Is your harddrive the primary master? You can check in your BIOS. Unfortunatley, DOS and earlier Windows systems would name the first viable (fat or fat32) partition it found, so if it was on the slave, it would still be c:. However, if it is a slave drive, it wouldn't be hda in Linux.
Also worth bearing in mind... some computers came with a hidden partition before the "c:" drive, so that could be hda1.
If I were you I would get a copy of something like tomsrtbt, boot from it and check to see what partition letter/number you should be using.
Just a couple of thoughts for you.