Maybe the SATA port you have it plugged into is enabled in the BIOS as "hot swap". This means you plug a drive into that port, while the PC is booted and running. I have an "external bay" built into my case to plug in a HD that take a SATA and SATApower cable inside the case, and I enabled that port to be hotswap, so if I need to, I can plug a HD right into my case to pull stuff off, wipe the drive, etc. I can also "eject" the drive, so I can remove it safely while Windows is still running.