VirtualBox uses its own drivers, but allocates memory for video and sound. You
can share a soundcard but only use one at a time. Also you may have to re-boot
your VM to get control of your sound in Linux from my experience.

When you install VirtualBox you need to have certain pre-requisites, but it is
easier to install them from Synaptic, the package manager, which will install
the dependencies. In comparison, VMWare requires VirtualBox is to add your user
name to Vboxusers Group in the Users and Groups section of the Administration
panel. Once this is done, Virtualbox is ready for use.

You can install any OS, but Windows is the usual one and it has some
peculiarities that make it difficult to use with Linux (a different file
structure, APIs and more). All in all it is amazing that VirtualBox can sort it
out at all. So do not give up easily. Expect problems.

In VirtualBox settings the sound card should be set for OSS. If your sound in
Linux does not work then shut off the VM and if worse comes to worse logout and
back in or even re-boot. I have not had to go the this extreme, but it should
re-set your sound settings. Not doing so would be an extreme situation, indeed.

Thanks for your reply. I've no longer got Virtualbox installed as I said
on my first message. Removing it was one of the things I did to try to
get sound and video back. No luck.

I'm still on silence and poor graphics. I don't know what to do, so
suggestions would be greatly appreciated. Do I have to reinstall/update
the whole system and lose all my settings?

I forgot to say: I've got Ubuntu 8.04 (hardy) 64 bits.

Unfortunately when people have problems and try to resolve them on their own
then they cause more damage than the initial problem warranted. In your case,you
have broken sound and perhaps video.

In the worst case you may need to re-install Ubuntu, but this can be done
without loss of data. In the best case you can get the proper drivers and
settings and continue without problems. Just be patient and do not do too much
without guidance and you may reduce the severity.

Tackle each problem separately. Ubuntu knows your hardware since it detected it
and set it up in the first place. It is just a question of finding what is
interfering and setting things up properly. Fix one then the other. Video is
more important. Get it back then work on the sound.

I don't know your card so I can't give specific advice. Post what is relevant
and someone can help.

Here's a related question that has been puzzling me ever since I started
into Linux...

In at least the earlier versions of 32 bit Windows when things got messed up
it was usually possible to reinstall without losing anything except perhaps
programmes that had become corrupted. Almost everything was still there and
working after a reinstall. I think that ended with XP (but I'm not
absolutely sure) which forced one to either do a fresh install in a new
folder, or trash everything.

Is it possible to reinstall Ubunto Hardy and keep the software that is
already installed? I know you can keep your home directory, but it would be
nice to be able to just do a "refresh" to repair anything that was damaged
in the main O/S.

believe you or not, I've got your message right when I was about
to wipe my current install and restart fresh.

I know it'd be a pain but it's been worse to work with my sistem as it
currently is.

> Tackle each problem separately. Ubuntu knows your hardware since it
> detected it and set it up in the first place. It is just a question of
> finding what is interfering and setting things up properly. Fix one then
> the other. Video is more important. Get it back then work on the sound.

I agree.

> I don't know your card so I can't give specific advice. Post what is
> relevant and someone can help.

Well I'm not so sure as I haven't got any help from anywhere I posted
help requests, which includes Ubuntu forum itself.

Anyway...

My graphic card is NVIDIA GeForce 8400.

Before the Virtualbox mess my Hardware Drivers feature showed "NVidia
binary X.Org driver ('new' driver)" and the graphic acceleration was
working normally. After, "NVidia binary X.Org driver ('new' driver)" was
gone and graphic acceleration stopped working. Both Add/Remove and
Synaptic keep showing "NVidia binary X.Org driver ('new' driver)" as
installed.

Since I haven't been able to get help anywhere nor could wait any
longer I decided to take the last and more radical choice: wipe the
whole thing and restart from scratch.

Now I've got back sound, video and Virtualbox (the villain of the
story) up and running.

So, whenever someone else comes here with a similar issue, you may
rest assure that the only effective solution is healing the disease by
killing the patient.

Yes you can. Check this out:
lifehacker.com/.../roll-your-own-ubuntu-live\
-cd-with-reconstructor-276092.php

Only, in their own words, it isn't fully operational with 8.04.

I have an nVidia GEForce card. I tried the open source drivers, but could not
get all of the features to work, so I use the nVidia proprietary drivers found
in the repositories. Go to System | Adminstration | Hardware Drivers. It will
tell you what drivers are available and recommend one. Try the recommended one
first.

That's exactly what I've been saying: Hardware Drivers shows nothing.
Zero. Nada. Just an empty window.

However, both Add/Remove and Synaptic say the driver I need actually
*IS* installed.

Congratulations, both on your successful installation and on your perseverance.
Now you can help others when their system goes down. Nothing like experience as
being the best teacher. It is hard to remain calm in such circumstances.
Computers can be frustrating and we are never quite sure sometimes why things go
wrong or what we did to make them right, even after years of trying.

Well, to be honest, the only help I could give in a case like that is
saying to the poor victim: "Congratulations, you'll have to back up all
your data, wipe your HD and restart from zero like I did". Not many
people will thank me for such a help.