i have many matematica notebooks and all of them are working clearly besides one which is the most important for me.There is my whole project.Please someone help me.What should i do???
I had your problem more than once. As @belisarius said, backup, backup backup. Very often that saved my day. However, in some occasions there was no backup. A possible but time consuming way is to repair your notebook by hand. I hope it is not to big. Using the solution given in the link provided by @Yves-Klett might reduce the file size. Make sure though that you do not overwrite the original. The provided code might not work properly if the code is corrupted and it might delete stuff that you actually want to keep. That said, the hard way really looks like this.
Open the code in a text editor (it is probably better not to use Mathematica for this)
Create a working notebook, save it, and also open it in the text editor
Copy stuff from (complete expressions of course) the original notebook to the new one and check if it is working by loading it in Mathematica after each step.
That's a painful job, but worked for me once. Sorry that I cannot help more, but maybe someone else can.
Update Thinking about the comment from @sjoerd-c-de-vries, ("...sometimes adding a } at the correct place may be all that is needed.") you might think about taking a text editor that provides a balance check on parenthesis. In Win you may have a look at Notepad++ in Linux you can take e.g. KWrite or NEdit