Ok. It took me the entire night last night and the entire day today to do everything I wanted to do with my PC.
I did a major upgrade to it and I'm giving away my old hard disk. That is the reson why I wanted to wipe out the entire disk. The Killdisk program I got from China's link did the job, but just to make sure, I also used WipeDrive.
I tried to look for a file to 'low-level' the disk but I couldnt find any in the WD site.
I did a (1) pass overwrite with Killdisk and a (3) pass overwrite with WipeDrive.
Thank you all for the help and inputs.