I've been having trouble getting 13.04 booted recently.
First I had trouble getting
grub working but I resolved that issue. I finally got it booted and installed the ATI drivers.
Now it goes to a purple screen after selecting Ubuntu and won't do anything. I looked that up and was told to try
nomodeset which also failed.
Then I was told to try recovery mode but whenever I select that it boots to recovery menu and immediately freezes.