Restoring a VirtualBox VM to a clean/default state?
You seem to want to preserve the configurations for the virtual machine.
The easy way to accomplish this is obvious: detach the virtual disk image and replace it with a new one.
The configurations for the virtual machine remain in tact, but the stored data is gone.
1. In Settings >> Storage, remove the current virtual disk image.
2. Add a new attachment: "Add Hard Disk".
3. "Create new disk"
4. VirtualBox will use the new disk.
For future reference, after you've installed the virtual machine and have everything running, create a snapshot. This will allow you to revert back to this squeaky, clean state whenever you want!
See Also:
- VirtualBox - Chapter 1: Snapshots