I've looked at many for ideas and suggestions (here are a few)
My computer boots to a black screen, what options do I have to fix it?
Ubuntu 12.10 desktop/interface not showing on VirtualBox VM after login screen
How do I install Guest Additions in a VirtualBox VM?
Can I install extra drivers via the command prompt?
I know these are of disparate topics - but I finally did succeed in installing the guest additions. To start, I have a triple boot and use the mac host mostly, so I put VirtualBox to access the Ubuntu partition. Worked in the past but upgraded to 13.10. Actually I can log in but after that I get a black screen. I've uninstalled Cinnamon and have tried editing the boot with the nomodeset to see if I can get a graphical interace to check the drivers. Even tried jockey-text. BUT, if I boot into the partition from rEFIt, then everything is fine. So I'm a little lost - any ideas?
P.S. By the way, even with the black screen I can go to a virtual terminal and log in and do stuff, but I need a desktop environment for work (working on GUI programming ;)
P.P.S. Also, after trying startx, I also get a system that hangs at "Loading extension GLX" in a virtual terminal - this was mentioned in another post that I cannot find right now....