I've recently set up ubuntu 9.1 via virtualbox and am having some issues getting things started.

First issue is when I boot up the virtual machine a warning box pops up saying virtualbox is optimized for 32 bit color and the OS is running 16 bit color. Some google searches revealed that for linux 24 bit color is what I want, but most suggested I edit the xorg.conf file to 24 bit depth. Problem is when I try to open that file it's blank. Further reading seemed to indicate that the most recent versions of ubuntu no longer use the xorg.conf file, so how would I go about switching from 16 bit to 24 bit color? Not a major issue but still annoying.

Second issue is firefox crashing when I try to open a website with flash like youtube with this ubuntu machine. Seems the site will load fine and I'll get maybe 1 frame of the video and a split second of sound. Not only would firefox crash, but the entire virtual machine would freeze. Only thing I've been able to find about this issue is that flash crashes seemed common with ubuntu 2 years ago, wasn't seeing anything about the 9.1 version.

Any help would be greatly appreciated.

About the first problem go ahead with the xorg.conf file. It may be that is no longer used by the actual Xorg, but it still does its job if you set up something manually.

About the second, it comes to my mind the fact of lacking some flashplayer dependency, but that in terms of firefox crashing when attempting to open a flash based web site.

About the virtual machine freezing itself, no clue

For virtualbox, just check the box do not show this warning again because it means nothing.