you DO NOT want to "burn to disk" a ISO !!!!!!!!!!!!
a ISO MUST !!!!!
be burned as a image !!!!!
you can not move it to a dvd as a DATA DVD
select "burn as image " !!!!!!
and use the SLOWEST SPEED say x2 or x4
Windows OS's do not have the software needed installed from the install dvd
as in you MUST !!! use third party software
if you already spent the $60 USD on "Nero " then use that
but there is a FREE program called "CDBurnerXP "
yes it's name sounds "fishy" but it is a real program and is GOOD
it will run on win7 64 bit and burn iso install DVD's
Yes it is possible to use a usb thumb drive
BUT ( and this is a BIG ONE )
it will be DEAD SLOW
i have a few OS's installed to flash drives and while they are "usable" i use that term VERY LOOSELY
10 to 15 sec or so open just a new folder
as in it takes a long time to open a folder once you double click on it
so LONG that you start to wonder it you really DID double click it
and you do it again and now after 30 sec you have the folder opened TWICE
and if you want to move a file that is say bigger than a few Kb ... that will take time
if it is a few Meg
say a 30 meg youtube vid
start coping it and go have dinner
it might be done in an hour
and the internet web speed
a 300 meg update for fedora 19 TOOK 9 HOURS to download and install !!!!!!
so yes you CAN use a usb2 flash thumb drive
now just your normal everyday dual boot is rather easy
a triple boot is even easy ( on one box i have Win7 64 bit, OpenSUSE 12.3 64 bit ,and SciebntificLinux 6.4 64 bit )
use the win7 disk tools the first
then re DEFRAG
then make space for the second os
( leave the new partition blank )
install your Linux OS to that second partition
mind you i prefer to let MS have the MBR and install grub to the FIRST linux partition
and "chaiinload" the grub win7 entry to the Windows bootloader