If you have ever wanted to know how data recovery works, I will provide you with an overview. Opposite to what you may think, when you erase a single file, it does not undergo the digital equivalent of shredding. Instead, all that happens is the reference to the written document is removed from the operating system index. So the single file still exists but the operating system does not know where to look for it because it has been removed and as such just can't be detected. Even so, data recovery specialists can rebuild the file index that the operating system needs to locate your computers file. When that is executed you can get 100% data recovery. Once you have removed a file, the room on the hard drive can be re-used & the original file will be overwritten.
Do not take the chance of having to telephone a data recovery expert. Back up all
Article by Steven Harney of http://www.hard-disk-information.com (The hard disk information centre)