you can't make it not detect it lol.
unless your format your hard drive first.
But you said you wanted daul boot. so i told you how to daul boot.
So as i said you can go to it when it gives the preious installation hit esc.
it takes you to next screen shows you your hard drives.
C:\ drive will have windows on it.
you can go to it HIT
D to delete it follow the instructions.(anything else on the drive will be deleted.)
you end up back at the same screen you press enter on the unpartitioned space. select what you want to do size of the disk how you want it formatted.
*"*"*"*"*"*"*
IF YOU HIT ESC IT CONTINUES TO NEXT SCREEN AS IF YOU DONT HAVE A COPY OF WINDOWS ON YOUR PC *"*"*"*"*"*"*"*
You can not stop it from detecting the version installed end of it does it by default its part of the CD which can't be altered.
Also post exactly what you wish to do because you don't make sense. you want to use new installed version but what the hell you gonna do with the version already installed?
you must format hard drive to get rid of it