[Matthew.V]

Hi there.

I'm having quite a problem right now...

I have an Ubuntu 8.10 CD, and I was trying to install that on my laptop. I chose the option saying "Demo and full installation", so I ran Ubuntu from the CD for a while, until I decided to finally install it. The installation failed, so I rebooted my laptop, and when it started up again, it passed the BIOS screen, but after that, I see a black screen with a flashing underscore.

PS. I cannot enter BIOS to boot from a CD or anything, because there is a password on the BIOS, which I don't know or remember putting on.

I would really appreciate any help at all.

[BG-0]

Well, the installation obviously seemed to already change your primary boot device to the hard drive, on which you don't have a working OS, so it hangs. You will need to get your hands on the password. We can't help with that (refer to the forum rules).
You could unplug your hard drive, start up the computer and hope that it boots from the CD. That's very little use however, as you can't hotplug the hard drive back anyways, so you can't install. This would however confirm that no hardware damage has been caused.