Why can I see a hard drive when it s installed into a laptop, but when it s connected to a USB External Chassis?

possible answers a) you may have compressed the c: drive because it got too full, it so its data is all mashed up(except when windows 7 reads it) b) the hard drive interface in the pc is 32 bits, but only 16 bits in the usb external caddy and the two halves mean the data is swopped eg 12,34 looks like 34,12 so its all jibberish(most bios's used to have manual settings for this but for about the last 15 years they auto sense the issue and untwist it for you, but usb thingies are too primitive for that kind of feature). so a clue then the Disk Managment features allow you to VIEW what partitions a drive has on it. a compressed drive will have a tiny C: and a big compressed d: ++++++++++ to recover your data, download and burn a hiren's 15.2 and boot it in the laptop that reads the drive, with the drive in it. then copy any data from that drive to somewhere else, eg usb stick or other drive. once you have saved your data, put your drive back in the usb thingy and delete all its partitions and make one partition on it and format it

Somebody has encrypted the drive! That's what they do! They work in the computer that made them but remove the drive an no worky