[CentOS] bad install

Mon May 20 20:42:52 UTC 2019
Doug <dmcgarrett at optonline.net>

I tried to install Centos on a partition of a Windows machine, and I 
screwed up. Thinking that the installation would take a while, I took a 
short break. When I

came back, the install was "done" but it is now asking for a password 
that I never gave it. I can't get around this. I tried to reinstall from 
the DVD I downloaded,

but it just comes up "password" instead of letting the DVD mount. I 
tried to reformat the partition (sda6) using gparted, but the section 
that contains the

problem does not reformat, it remains there. The Centos version was 
downloaded on April 26, and it is called "CentOS-x86-64-DVD-1810.iso." 
It is a new computer

called PowerSpec B741 and there is no manual for it, apparently not 

Suggestions please! Thanx!