Sometimes you will need to place the drive on a second computer, then do a complete slow format. OR a computer tech store can erase it for you.
Or bulk erase the drive, then try it again.
A malware program, or the security already on the drive may stop the drive from being re-formatted by the usual methods.
It can be reformatted by other means such as above.
However, a 1TB drive can be a poor choice, if you plan to put the OS on the same drive as the personal files...it will run pretty slow.
It's better to use a small fast drive (like 70GB) , for the OS and applications (only),
and use the 1TB as a second drive, for your personal files only (default save location).
This way the system will boot much faster, and the core applications will be much faster.