I have 2 pc's and I want to swap the hard drives. Both have XP sp3 one is 20 GB the other is 80GB?

Jumpers on both set to CS. took the 80 GB from a Pentium III 930 MHZ installed it in a MS-6378X-L Athlon 1.7 GHZ. Now it won't boot, getting a message "floppy drive failed" referencing the secondary slave drive, which there is none. Any suggestions?