How to recover accidentally deleted data on a computer

In many cases, files that have been deleted from a hard drive still exist until new data overwrites them. If data recovery programs can find these files before they are overwritten, you are in luck; the chances of recovering your data are quite high.

If a file is accidentally deleted or becomes inaccessible due to a hard drive failure or file system corruption, remember the golden rule of data recovery: Act quickly! The more you use the hard drive, the higher the likelihood that your data will be overwritten and lost forever.

If files are deleted by: emptying the Recycle Bin, or by pressing Shift and Delete at the same time (to delete directly without going through the Recycle Bin), these files are not actually gone. Windows only changes the first character of the file name in the file storage system. Therefore, these files will be ignored by the operating system. Windows simply marks them as free space available for storage, allowing other files to overwrite them. To recover deleted files, you need tools to restore the original file names and remove these markers before Windows and other applications overwrite them.

The SystemWorks 2006 toolkit (priced at $70) from Symantec includes file recovery programs. Another trial program is EasyRecovery Lite 6 (priced at $89) from Ontrack. There is also a free utility called Restoration by Brian Kato.

If you are using Windows XP or Windows 2000, ensure that the programs you choose support the file systems you are using. These may be the FAT format (rarely used), FAT32 (commonly used in Windows 98, ME), and NTFS (used in Windows NT/2000/XP/2003). Windows 98/ME cannot read NTFS file systems. Windows NT/2000/XP/2003 can read all FAT, FAT32, and NTFS file systems. Unsure about the format of your hard drive? Select My Computer, right-click on the hard drive icon, choose Properties, and check the File System on the right.

When you format a hard drive, you create an index for each file on that hard drive. This index is known as the FAT (File Allocation Table) in FAT32 and MFT (Master File Table) in NTFS. If this index becomes corrupted due to a virus or is overwritten by formatting, Windows may not be able to find the files on this drive.

Data recovery programs can recover the FAT and MFT from backups or recreate the structure. If this index is irreparable, good data recovery programs can still identify and recover lost files.

Norton Disk Doctor in System Works, Scandisk in Windows 98, and Chkdsk in later versions of Windows can identify bad sectors and move your data to “healthy” sectors while marking the damaged sectors to avoid writing data to them. However, these utilities do not recover much data.

EasyRecovery Lite not only recovers lost files but can also recover and partially repair corrupted files like Word and Zip. EasyRecovery Lite has a raw data recovery mode (RawRecovery) for damaged hard drives, where no folders exist.

EasyRecovery Lite also has an appealing feature; this program can recover files even after the hard drive has been reformatted. In this mode, EasyRecovery will slowly scan the hard drive. This program can run from a bootable floppy disk or from the installation CD. The EasyRecovery Lite version limits recovery to 25 files per session. If you need to recover more than 25 files or support more file types, consider EasyRecovery Professional (priced at $499). This premium version can repair Office documents and includes hard drive diagnostics.

Minh Phúc