SD2 hard drive wont open

[Padbash]

my hard drive was working fine and now my computer wont even see the hard drive when connected, i have lots of personal stuff that i dont want to lose

 

[RolandJS]

Far wiser techs than I are going to ask you for details, such as external USB? HD enclosure? NTFS [GPT or MBR]? I had a couple of flash sticks that suddenly refused to flash [work] anymore. I sure hope your HD can be brought back to life w/o reformatting. Can you attach to another computer? If so, what happens? Exactly what error message [if any] do you get?