Drive not recognized in "My Computer"

I just installed a 320GB Blue drive in my computer.  The “Hardware Manager” shows it in the list but it is not on the “System” in “My Computer”.  Did I miss something somewhere?  I plan to put everything on this drive because one of my diagnostic programs warned of imminent drive failure on the original (7 years old) drive.  Someone suggested that I may not have set it up in the BIOS but I can’t remember how to get into it.  Can someone here help?  Any assistance will be appreciated.  Thanks.

Same problem with a WD20EVDS under Vista Ultimate.  Not listed in My Computer.  Listed in System hardware, showing no problems.

Can you go into Control Panel - Administrative Tools - Computer Management - Disk Managment and see if the drive is listed as “Online” or “Offline”?

Thank you.  I forgot to go into Computer Management to format and allocate.  Too long since I had installed a new drive. 

Hello!

 I have the same problem - and right clicking on the disk says it is offlne. Any action i do on it gives a message ‘incorrect function’. However, the drive is working properly. Can you please help me get back my data?

Thankyou.