First hd is not suport windows

Hey friend i am two hard disks. First 80 gb
and second 380 gb.
80 gb hard disk is pata cable and 2nd is sata cable supported.
When i am atach 80gb
hd with my computer,
the massage showing on startup 'insert the proper boot disk device'.
But when i am atach 2nd hd with his.
The first and second hard disk working properly. And i am only able insalling window in 2nd hd , not in 80gb hd .
Please help me