Running virtualbox on a pc. I have virtualization enabled in BIOS. Installed Ubuntu 12.04 32 bit on virtualbox without 3d acceleration enabled and it works fine, but when I enable it and restart, the desktop shows up but there is nothing on it or on the top menu bar. Things are clickable where they should be but you can't see what you're clicking. What's wrong?
You need to install the VirtualBox additions for your virtual machine and also enable the 3d support in your virtual box settings.
Have you done both?
I have also experienced this problem on a Windows 7 host, and as 3D acceleration is default for VirtualBox, it took me ages to find the solution. In my experience, it is an intermittent problem - most of the time it did not work, occasionally it did work.
I installed VirtualBox additions but it did not resolve the issue.
This is what worked for me:
Untick the "Enable 3d acceleration" under display, and Ubuntu on VirtualBox is stable although slightly less glossy.