Some more details might help.
Previously, I had the installation on 1 of the 3 hard drives, and I mounted the other two after I had previously installed cent os.
I have since then unplugged the hard drives, leaving just one. Still no luck :\.
The desktop's specs:
ASUS A8N-SLI Mobo
AMD 64 X2 3800+
I was trying to install the X86 edition of Centos, but that shouldn't make a difference, right?
Thanks again for your help