If you are sure you have 2 physical drives and not 2 partitions on one drive, it can be done. Some think that they have 2 because they see C: & D: where D: is the recovery partition.
Turn on the pc and enter the bios screen, change the boot order so that the dvd drive is first boot device and save settings.
Use the Windows 7 dvd to boot with, select custom instalation and select the 2nd drive to install W7 on, then continue the instalation. Windows will create a menu for dual booting.
You may need to get some W7 drivers for your laptop, check out the makers website to see if they are availble.
jonmor68 thank you for the info. yes i have 2 physical drives i have a hp pavillion dv7 with 2- 320gb drives but i down loaded windows 7 to the drive i do not want to install it on. now what?