If you downloaded Ubuntu from the Ubuntu site, you need to verify the download by doing an md5check. Should be instructions on the download page. Then use CD/DVD burning software to burn the Ubuntu iso file as an image, do not copy as data. When that completes, place the Ubuntu CD/DVD in the drive, reboot your computer and enter the BIOS setup (on HP, usually by repeatedly tapping the F10 key - it should show at the bottom of the screen when you see the HP logo on boot). Then go to the Boot tab and change the order to put your CD/DVD drive to first boot priority, save the changes and exit and continue the boot process.
when I try to run it the installing ubunto comes up and requests password,
What does "try to run it" mean? Are you running it inside windows8? That won't work. Are you booting the CD/DVD? There should not be a request for password. What password are you entering? Since you haven't done the install, there would be no password for Ubuntu. The Live/Install CD/DVDs do not have passwords.