Sounds like grub was installed on your new linux drive but bios is set to boot from your windows disk. Many computers you can press f11 several times when first starting and you get a menu where you can choose the disk to boot from by pressing down-arrow a few times then enter. If you turn the power off in the back and turn it on, supposedly these menus are in the same sequence. Then whin linux boots you could put grub on the MBR of your windows disk if you dare.
