Jan upgraded his old netbooks with Ubuntu. But when he booted up, he ran into trouble. Leo says that most Linux installs have a boot CD mode and it's a good idea to try booting from that before installing it so he can see what works and what doesn't. Jan got his way through it and booted it up. Everything works fine. But when it turned it on the next day, he got nothing, just a command prompt. Leo says that it may be the install wasn't done at after all, and Jan just booted without the CD. So boot back to the DVD and run the installer.
Leo also says to remove everything from the disc drive and USB slots. If that's been done, then it sounds like the boot loader isn't running right.