Ubuntu won't start after deleting a copy of some kernel files

Ubuntu won't start after deleting a copy of some kernel files

Ubuntu 13.04.
Here's the problem. I was browsing through my photos the other day, and as
soon as I had a kernel problem last week, I accidentally skimmed C:/ and
while not looking, copied the wrong folder.
I left it until today.
I deleted the copied folder, and it said I needed to restart to enable the
changes.
Now, when I boot, Ubuntu's splash screen shows, then it turns to grub. I
am using a old kernel at the moment, and the new one is gone.
Thanks in advance.