Hi Gee,
It seems that, you need more information to recover data from HDD 400GB.
When you Perform chkdsk on the hard drive if any bad sectors are found on the hard drive when chkdsk tries to repair that sector if any data available on that might be lost.
Use your favorite search engine and find the application which helps to recover data from the HDD 400GB.
Note: Using Third Party Software, including hardware drivers can cause serious problems that may prevent your computer from booting properly. Microsoft cannot guarantee that any problems resulting from the use of Third Party Software can be solved. Using Third Party Software is at your own risk.
You can also refer to:
How can I get Windows 7 to read RAW hard drives without having to format the hard drive due to important work on it?
Hope this information is helpful. Please do let us know if you need assistance with Windows, we’ll be glad to assist you!