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.