my pc is not reading both my hard disk

[santosh002]

While starting it shows boot failure insert os disk in DVD drive where as I have two different os in each hdd

 

[Phillip Corcoran]

Do you get boot failure when trying to boot from either of those two hard drives?
It's unlikely that two physically separate hard drives would both fail at the same time (unlikely but not impossible).

Check that none of the data or power cables to the drives have become loose or disconnected.
Replace existing data cables with new ones as they may be faulty.