As a general rule try to keep your data on a separate drive from your system if using a desktop, this will ensure your data is safe if the system fails. If using a laptop then follow the advice given and buy an external USB drive. This will ensure your data is more secure. I use the best of both worlds with my desktop using 2 HD`s and the important data always backed up to an external drive. The initial outlay is worth it if your drives fail.