Is it possible to dual boot between Ubuntu and Windows 7.vhd? If anyone knows please tell me how?
You need to either get grub to pass over to the windows boot manager, or boot linux via the windows boot manager.
Go with the first approach to begin with (I would trust Grub more).
...but that's pretty much what Ubuntu would make for you anyway. Which operating system did you install first? Or are you yet to install Ubuntu?
If you are yet to install, do not install grub to MBR! You should instead install to the first sector of the /boot partition. Otherwise, you're going to overwrite the windows boot manager.
The alternative is to do the reverse; let windows start grub. No idea here, your mileage may vary and all that.