Asus Striker II extrem wont boot most of the time

I have Asus striker II extreme motherboard and WD velociraptor 300gb.

They have been working together fine for the best part of a year.

Now, when I turn computer on, most of the time it will not pick the hard drive up and display "missing operating system" or "boot failure" message. 1 out of roughly 5 times it will boot fine and computer will operate with no problems.

I have tested the hard drive in another computer it works fine.

I have tried different SATA port and different power cable but no luck.

I have not performed any software or hardware installations recently.

I attempted to reinstall windows, however I came across the same problem where the hard drive was not recognised.

Yes, I have tried a different cables also