I must have accidentally installed Ubuntu alongside of windows 7
What exactly does that mean "must have", either you did or you didn't. You would have to give us a little more to work with like the type of installation for starters. One hard drive? multiple drives? installed Ubuntu on its own partition? wubi install? Are you using the Ubuntu Grub bootloader to boot both Ubuntu and windows? Are you using the Ubuntu booloader from your other Ubuntu install to boot everything? If so, you need to repair the bootloader and get windows on the mbr first. Can you post drive/partition information booting the other Ubuntu and running: sudo fdisk -l(lower case Letter L in the command).