you have to have everything plugged in when you install ubuntu, it will over write the MBR on the primary drive so you can boot either one, just DO NOT LET ubuntu format anything but the drive your installing ubuntu on
please, go to ubuntu's website and start reading their tutorials, they have excellent documentation, before you screw something up and/or get frustrated further
what happened was ubuntu got installed but it wrote the bootloader to the drive its installed on rather than the primary drive which has windows on it, so when your PC boots all it does is boot windows ike normal
you should be able to boot it up anyway, but you will need to use the ubuntu disk, just tell it to boot up instead of an install..........how to do this varies a bit from distro to distro but a prompt should be present early in the process where you can enter the drive to boot from instead of an install--------> probably have to type something like /dev/hdb1 depending on how you have your drives set up
your probably gonna have to einstall ubuntu yet again cause you dont know what your doing