If you are positive that is connected correctly and your jumper settings are correct, it may not recognize anything larger than 32GB or even 8GB if it is really old.
While modern IDE controllers will address drives larger than 32GB, older systems circa (about) 1999 or less aren't always capable.
You have four options (listed in the order or effectiveness).
1.) Update your BIOS from the manufacturer with the latest version. Many board manufacturers have updates for their Pentium II or better boards which offer >32GB capability.
2.) Buy a PCI IDE controller. They use their own BIOS to recognize the drive and anything you buy new will be able to recognize 32GB or greater.
3.) Use a drive overlay program to "fake" the computer into access all 80GB. Not recommended[/b]. This could cause serious data loss in the future, although it should work fine if you never run into file system related problems.
4.) Many drives above 32GB also have a "32GB clip" jumper setting which limits the drive to 32GB total.