I installed Ubuntu 12.10 64 bit on my hard drive, then decided to install Windows 7 alongside on a 25 gb partition. I shrank my Ubuntu install by about 25 gb with a GParted Live USB. Ubuntu booted correctly after the shrink. I shut down and installed Windows 7 on the 25 gb partition. Now Windows 7 boots, and Ubuntu doesn't. Did I overwrite my MBR? If so, how do I fix it?
Use EasyBCD to edit the Microsoft boot manager, too add ubuntu on to it. Then boot up Ubuntu and install Boot-Repair and reinstall grub and that should take care of it and set the default boot manager back to grub.
Just post a comment if you just need me to go into more detail on this.