You mention that you're trying to "upgrade" something.. Please describe exactly what you are trying to do.
To clean off a hard drive and install a new operating system, you simply need to place the new, legal operating system in the DVD/CD drive, let the system boot from the CD, then use the disc's instructions to delete all current partitions, then format the drive and install the operating system.
On the other hand, if you simply want to wipe a hard drive so secure and nothing remains, then using a boot disc such as the one at the DBAN link below should get it done for you.
Hope this helps.
I need step by step instructions on how to completely erase my hard drive (Windows Vista) and after that install Windows 7 operating system. I've failed at this type of upgrade in the past.