Sometimes you have partitons in your hard drive which all of a sudden vanishes and you just can not find it. Making the situation worse your bootable drive isnt booting now. It becomes a mess and you can do is call for assistence.

Technically both the problems happens because of the mapping lost i.e. The partition table got corrupt. This is where we can use an excellent freeware software called as Test Disk. Its a command line utility which also works with LINUX.

The menus are simple to understand but still you will need  to be careful and patience when you use it. In can fix even your non bootable partition the most common problem I had face and when i dump linux which is already installed over windows and it always looks for GNU bootloader.

It says

TestDisk is a powerful free data recovery software! It was primarily designed to help recover lost partitions and/or make non-booting disks bootable again when these symptoms are caused by faulty software, certain types of viruses or human error (such as accidentally deleting a Partition Table). Partition table recovery using TestDisk is really easy.

Features of TestDisk :

• Fix partition table so that we can recover deleted partition.
• Recover FAT32 boot sector from its backup
• Rebuild FAT12/FAT16/FAT32 boot sector
• Fix FAT tables
• Rebuild NTFS boot sector using backup also.
• Fix MFT using MFT mirror
• Locate ext2/ext3 Backup SuperBlock
• Undelete files from FAT filesystem
• Copy files from deleted FAT, NTFS and ext2/ext3 partitions.

Here are some snapshots: