Okay I downloaded DBAN and burnt it into disk, inserted it into slot and selected run from disk and itr didn't do anything, I burnt two cds and I made sure DBAN was on both of them

You need to BOOT from the disc for it to work.
You can't format while the OS is running.

Yeah I selected the boot from disk option, however when it is meant to say "press any key to continue" it just skipped straight to the windows loading page. It's a pre built computer so Microsoft may have put on defense stuff on it so people can't remove their junk.