If you installed Backtrack and it is now the only system that boots, it is a pretty good indication that it installed its bootloader to the master boot record. Does Backtrack use Grub2? If you were to delete the Backtrack partition in this case, you would not be able to boot anything because most of the Grub files are on the Backtrack partition.
I tried the restore disks that I created when I got the laptop
Are you referring to the windows 7 Recovery Disk? That should have worked to boot windows. Did you have a Recovery partition for windows? Did you install anything over it?
What do you have in the Backtrack /boot/grub directory? Does it have a menu.lst file or grub.cfg?