I can't understand this I hope someone else can. I have a 500GB Toshiba portable hard drive. It is showing that it is completely empty, including the pre installed software, (how that happened, I do not know), but has 31GB of room. I am trying to backup my computer but it of course is saying it isn't big enough. I have been trying to figure out what happened to the preinstalled software also so I can get that back but no luck. Thanks for any help.
This has happened to me also in the past, but with a flash drive. To get a better view, try looking in Disk Management (which can be found by clicking "Start", right click on "Computer", then click "Manage". Disk Management will then be under the Storage tab). This gives a detailed view of how all of your drives are split up, whether it be physically or logically.
Your drive should show up down there, and probably is split into a couple different partitions. If you right click on the different partitions, you can choose to format, shrink, extend, etc. You'll probably want to right click on each partition listed after the first one, and delete. They should now be showing as "Unallocated." Just extend the initial partition to 500 GB (or whatever the max is), and you should be good to go.
Be careful when you do this, and make darn sure you're configuring the right drive--the last thing you want to do is mess up your primary hard drive (or SSD), and have to format reload Windows all over again.