How Can You Retrieve Lost Data from a Western Digital Hard Disk Drive?

Is It Possible to Recover Lost Files from Western Digital Hard Drive?

I have a Western hard disk drive. I partitioned the hard disk drive into 4 partitions on my HP computer. Today, when I open my computer, one of the partitions cannot work properly. Whether I double click on the partition or right click on the partition to open it, it always shows an error message which says: disk in drive is not formatted do you want to format it now? I know there is something wrong with my hard disk, but I really want to get data off the partition before I format it. How can I do it? Please give me a hand.