Maybe you can re-format your 40gb hd without partition magic... You can use fdisk... Usage of fdisk may seem difficult, but believe me it isn't... My advice is, boot your system with a bootable cd which could be knoppix or maybe gentoo live cds... When you get in to linux environment (linux console
) you can simply 'fdisk -l /dev/hdc' to see how your hd looks like... before making any changes, read fdisk's man (man fdisk) carefully.
Maybe fdisk could solve your hd problem [by saying solving, you can reformat hdc(40gb) with fdisk]. Then you could be able to install red hat with your fresh formatted hdc
PS: That's only my advice