You know that burning feeling deep in your belly when you realize you've misfired an inappropriate or scathing email (statement, not question). It's the same one that strikes when you realize some important data has gone missing from your computer.

The key difference, however, between the two scenarios: The former's salvation involves a tail and legs, while the latter stands a shot at resolution courtesy of five data-recovery software tools with one extra bonus for small-budget small businesses: They're all free.

"While the best defense against data loss is redundant and real-time backup, we understand that sometimes data loss sneaks right up on you," writes Lifehacker's very understanding Jason Fitzpatrick, who late last month asked readers to nominate their favorite free data-recovery tools. Some 3,125 weighed in, and from that collection Lifehacker's latest "High Five" list emerged. Those top tools, in order of most popular, comprise:

1. RECUVA
Operating system: Windows
Highlights: Uses a green/yellow/red light system to indicate how probable the recovery of your files will be; file-recovery wizard can help when you're sure your data is gone but you're not quite sure where it went or how to get it back, narrowing search by file type or computer location; works in manual mode if you already know where to look.

2. TESTDISK
Operating system: Windows/Mac/Linux
Highlights: Performs basic file recovery like undeleting accidentally deleted files; copies deleted files from partitions to recovery media; finds lost partitions in dozens of formats to help you locate your lost data; rebuilds master boot record.

3. PHOTOREC
Operating system: Windows/Mac/Linux
Highlights: Companion program to No. 2 TestDisk but tool in its own right for a lighter search; works in read-only mode, ignoring partitions and file systems.

4. UNDELETE PLUS
Operating system: Windows
Highlights: Like Recuva, assigns a recovery probability to files it finds based on how damaged the file is; sets filters based on time and size to avoid sifting through every deleted file on your disk; keep sfolder structures intact during recovery.

5. RESTORATION
Operating system: Windows
Highlights: No-frills, portable recovery tool that includes basic file-name search and the ability to sort by file parameters, such as size and file name.

Any others you'd like to add to the list? Let me know in the Comments area below.