i have 2 partition
1\ c 43 gb
2\ d 1850 fb
i'm using windows 7 , and I suddenly without doing any thing found my partition (d) disappeared ,then I open disk management and found it showing as a free space with the green color
please help it's one partition which has all my data
Could you check what option do you have when you right click the drive in disk management? Just check what options are active because selecting some of them like format or initialize will erase your data. It would be helpful to assign a drive letter, if that option is available.
I would recommend you to connect the drive to another PC as a secondary drive and try to access your files. Another option to save the data is to search for some data recovery tools. Check the Downloads section of this forum for some suggestions. Let me know if there is any progress.