Deleting a bad operating system

This is a computer problem. The other day my Diskeeper Ddfrag program

quit on me with the messege " diskeeper could not initialize" and my

generis windows xp home defragger said " defragmenter could not start"

so i ran chkdsk twice and no problems found then i tried system

restore to no avail. Then i tried to rerun windows with the option of

saving my files and got the blue screen that said that a error has

occured and to try to protect windows it will not start. So i rebooted

again and now i have two windows xp homes operating systems to choose

from with the exception that one will not boot up. So my questions are

how do i get my defragger or diskeeper to run again and how do i

delete the other windows xp home that will not run when i boot my computer up? My email is [email protected] thank you

Doug