Help me figure out if i have another dead H/D on my hands?

I have a Western Digital caviar black 1tb Hard drive and i need to figure out if its dead because my comp started slowing down in the last 3 days. Then it took forever for it load windows and the last time it did. i tried to do a virus scan but when i came back later i got a black screen with the message that the drive was unreadable. Now it wont load up windows past the windows logo. i have windows vista as my operating system and i have tried to put the installation cd into the machine to see if i could use it to repair my windows install but that is not working either.

 

youre gonna want to download western digital's diagnostic software. You can burn it to a cd and boot from it
http://support.wdc.com/product/download.asp?groupid=613&sid=30&lang=en

select Diag504fCD.iso and use a burning program to make the disc. Make sure you have the computer boot from the cdrom first (could be why you cant boot your vista disc)