My passport won't show up and can't format it either. Help please

I have a wd 320gb passport hard drive. When I connect it with my laptop some time it does recognize some time it doesn’t. Some time it says drive need to be formatted before i can use it. when i click format it takes 5min and says windows is unable to format it. When it shows up and I click over it, it takes too long to respond and says its not accessible. Volume doesn’t contain recognized file system. please make sure that all required file system drivers are loaded and that the volume is not corrupted.  I tried data lifeguard diagnostic and it failed to pass the test. Tried to write zeros and thought it will solve the problem but it was taking too long so had to stop it.

Went to the disk management and on the drive list it says type is basic and file system is RAW status is healthy(primary partition). I am using win7 64 bit. Please tell me how to fix that problem??

Use TestDisk to mount and fix the partition

Edit :

you can also use this