Older systems can only recongize up to 137 Gigabytes, newer systems can recongize up to 144 PetaBytes..
Much Older Systems, using LBA mode can only recongize drives 10GB or smaller.
And the size gets smaller as you go back through the years.
If you have an older BIOS and don't want to flash it, I think you can buy a controler card that will allow it to see bigger drives.