Say you have a computer that won't boot up. Maybe the OS is corrupt, or the motherboard has popped capacitors, or whatever. The user wants to salvage whatever files can be salvaged from the hard drive. If the problem is with the motherboard, you may try to put the hard drive in another PC -- assuming it has the right kind of connectors -- but you still might face the aforementioned corrupt OS, or the computer itself may refuse to boot because the hard drive has an OS that was tailored to a specific manufacturer's computer.
Puppy Linux to the rescue! It boots from a CD without disturbing the contents of whatever hard drive you have hooked up. The desktop's Connect icon lets you get on the network and do your Internet and/or local network browsing. The Drives icon lets you see the available drives and mount them with one click. (Hard drives, CD readers, flash drives, et al., stay inert in Linux until you tell them to become active.) The menu->network->LinNeighborhood option lets you add a Windows machine with shared drives -- enter the IP address, click Query, do a Scan as User or whatever it's called, and you have access to a shared Windows drive.
As you can see from the above paragraph, there is a little bit of a learning curve, but once you know what to click, everything is quick and (so far) painless. Today I rescued files from two different hard drives -- one set I copied to a shared network drive, the other to a flash drive. After decades of hating and fearing computer hardware (and networking, and pretty much anything that wasn't pure creation of code ex nihilo), I'm finally starting to enjoy it! Of course, it helps to have access to a never-ending supply of worn-out PC's that you can experiment upon without fearing the repercussions.