[peterpota]

Some people may suffer the situation of losing one or more partitions. Before you start the big task of repairing your computer in this situation, there are some tips you must know.
Understand what a file system is and how it works. An operating system uses a file system to arrange and store data on a free space or a storage device. You can write and read data on the file systems. File systems create partitions that are areas of free space seen as logical drives--for example, drive "C, D, E" and so on.
Find out which partition is having problems. Usually an indication of a partition that is having issues is that the files are missing, you cannot write additional data or you cannot boot up from that partition.
Avoid writing additional data on the affected partition.
Do not create another partition if you have deleted one by accident. Just leave it blank.
Transfer the drive to another computer if you are unable to boot up yours. Choose another computer that uses the same the same file system as your damaged partition. Transferring the hard drive to another computer will give you two benefits: it prevents writing more data to the problematic partition and allows you to retrieve information from the disk by using Windows Explorer.
Read your hard drive using a different operating system in case you have damaged or erased essential operating system files but you still have the partition information still intact.
Avoid reinstalling your operating system if you do not have another computer to move your hard drive to. Doing so would overwrite your files. If you have a back up and it is current, you can reinstall your operating system and then recover from back up. However, even if you have a back up for you just finished a long day’s work which you have not backed up yet, you may want to re-think it first.
Use software available in the market that will allow you to boot from your computer. Use a DOS boot disk to try to boot up your hard drive even with an operating system that does not work.
If the steps are too complicated or the situation doesn’t allow you to do so, you can try a data recovery application. Now, there are a lot of software like that and some are quite useful.