In /etc/group, there needs to be a vboxusers group created, if it doesn't already exist. You need to add your initial user account to this before you can use the machine properly.
shows loaded modules.
Be sure you have vboxdrv installed and loaded.
If no return for vboxdrv,
then :
.
Also use the search function in synaptic and vboxdrv for the search term. Use option "name and description" to find reference.
Unless you are running intensive graphics rendering programs and using a multicore system simultaneously, swap doesn't need to be large. You can get way with 512M for swap size.
Install blackbox, fluxbox, xfce, etoile, or enlightenment- The first two are better, use right click, and are light on resources- and use the command line. You're going to be using kde services from the start and this will cut it down to only what needs to run.
What distribution are you running on the vm and what is it- Linux, BSD, solaris, etc?