Do you know how to use the linux version of fdisk?
Do not panic as your partition and data are not lost,you only need to go back from where you started.
I believe the hard disk not found message is becoz of the fact that you installed linux in the only primary partition.
So what you need to do is check out a utility like testdisk ( http://www.cgsecurity.org/?testdisk.html
and after recovering the partitions you can use fdisk
read the manpage before you do anything
(the command is