Ok so I just recently starting trying to fix up this desktop computer to use a new social computer for myself, but I had been having trouble trying to get the OS onto the harddrive. Eventually I got it to work, but I soon discovered there was a window 7 OS on it already. I asked my friend who I obtained the harddrive from and he said his dad did something with the computer the harddrive came from and then it didnt work at all. (Note the harddrive has been put into a different computer entirely not the same one) So now my question is how do I wipe all traces of data off this harddrive without rendering the harddrive unuseable. (Also as a side note I cannot access bios or anything of that such.)