Recently I decided to test natty, so i download it and try to install it on VirtualBox (v4.0 - 3D Acceleration Enabled) but have problem in using unity (It says to change my desktop to classic...)
Now I want to install it on my PC, so I came here to ask is it safe to do that?
Sure!
It's safe when you resize your partition to have about 20 to 30 GB unused space. Then you install from scratch using this unused space, leaving your system untouched. Just don't mess up your partition names during this process. If done right you'll get a dual boot system that way!
There should be an option within the installer to resize your partition during the install process if you start the installer from the live cd. Be careful when the bootmanager (grub) gets it's entries, not to mess it up. But even this would be easy to fix afterwards.
BUT:
If you are not familiar with the install process I STRONGLY advise to try the whole procedure of the parallel installation on your Virtualbox disk (the one you already have a natty system running on) BEFORE running on your productive system! Also remeber: Natty is still alpha status, so I would suggest a test run on a virtualbox disk in any case!
Good Luck, Have Fun!
cya, piedro