Formatting a disk only removes the pointers to the data, the index.  Formatting is like ripping out the table of contents from a book.  You may not know the chapters or topics, but the words are all still there to be read. The evidence itself will remain until overwritten by new data. If you were to inadvertently format a drive by choosing the wrong drive from a list, for example, the vast majority of the evidence will be recoverable, most likely without significant damage to documents.  Stop using the computer’s disk and call your computer forensics examiner.