Plan on the backup taking about 60% of the space USED on whatever you back up. Depending on how much of that 680 GB you're using, you might want to get a 2 TB external hard drive. My Dell Inspiron 660 has USB 3 ports so I assume you 680 does too. You'll definitely want the speed which is about 3 times faster than USB 2. If you have some static data you don't want backed up, you could partition your drive and put the data you want excluded on the other partition.
I suggest you get away from the Windows backup program and get yourself a good commercial backup program. I've seen forums fraught with problem reports for the Windows one. I know I was very unimpressed when I tried it. Three I'm familiar with and like are Norton Ghost (which I've been using since 2004 without the 1st problem), Easeus Todo Backup Free, which you can download from http://www.todo-backup.com/products/home/free-backup-software.htm and Memeo which has a 30 day free trial and you can buy it for $29.99 - you can download it from http://memeo.com . You can get Ghost for next to nothing (like I did) if you watch the sales.
The March 2012 issue of PC World was very high on the FREE program from Easeus and so is CNET. In my experience with a variety of configurations I have to say I'm very impressed. Like Ghost it will back up to a networked drive, and it will create a boot CD for when your PC won't boot. See CNET's review of it at
CNET has a lot of backup program reviews at
Some of these are free (last time I checked there were over 300), some have free trials (over 1000), and some are purchase only (over 200).
External hard drives are best for backup. It's the best insurance you can ever buy!
I hope this helps. Good luck
I've been working with a Dell Inspiron for a few months and I want to set up a better back up system. My hard drive is 680 Gig.
Some of my files are static and not changing, like videos and audio files. Other files are documents and files saved from various software, and, of course, I have software and system files that have saved configurations that I would not want to lose.
I'd like to learn more about how to back up a system this size; what alternatives are available; how to restore the system in case my hard drive fails. I'm working from my home and I'm on my own.
Can anyone tell me how I can set up a good back up system?