Help with Hard Drive (s)

I have 2 pc’s with the same mobo’s (ASROCK K7S41GX), one of which has worked 24/7 for over 2 years until now but i accept its redundancy. The problem is the second machine, having tried differant HDD’s and ribbon cables i keep getting ‘ATAPI incompatible’messages and a failure to recognise either HDD or CD/DVD drives.
Both machines are set up identically, I’ve tried resetting the CMOS etc, jumpers are set correctly on drives etc.
Any ideas please as i cannot see what i am missing and its getting ******** annoying
lol