This means that grub, as an application, has managed to load successfully, but something has stopped it from moving on to ubuntu. chances are this is a problem with the configuration file; although i'm surprised this happened on a fresh install.
The grub> prompt should allow you to restore your system.
As it's difficult to diagnose exactly what is wrong from just knowing you're dropped into the prompt, I recommend you read-up on this:
Simply however, I suspect you'll need to do the following:
- Seek the linux partition:
- Pick the parition you think you installed Ubuntu on
- Check that the linux parition has all the files:
ls (hdX,Y)/boot and
ls (hdX,Y)/boot/grub should all return the names of some files
- If not, change to another parition or come back here with the output
- Start the loaded menu:
- If this doesn't work, come back to askubuntu, or, if you're up to it, you can read how to write a rudimentary configuration in the link I included.
- Once you've got to Ubuntu in the terminal you must
sudo update-grub to save changes.
Personally, if this is a fresh install, I might take a pop at just reinstalling Ubuntu and taking note of the more advance options, specifically where to install grub to.