Check all the cable connections, power supply, and make sure everything is configured in the bios. Check your boot device order as well, though if it can't recognize that may not be available.
What kind of harddrives are they, can we have any more details. It is tough to tell exactly why it can't see them, but there are really three options
1)Hardware is damaged
2)Hardware is not connected or configured properly
3)Bios is not configured correctly
It is very strange that it can't see any of your drive, especially considering CDROMS should be an autodetect. Is your motherboard ok, how are the connections?
Lastly if you have a floppy, you may want to try flashing your bios to the latest version, but be careful your computer does not shut off during the process.
Also, try booting with just your primary hard drive in. I am out of ideas for now, but I am sure some other board members will give you even better insight. Good luck.