some of the application on my mac book not functioning

Hello SHYAM KABRA,

It sounds like some of your applications are not launching at all. I recommend the following article to help you troubleshoot the software, named:

Mac OS X: How to troubleshoot a software issue

http://support.apple.com/kb/ht1199

If the issue occurs in various applications, or in Mac OS X

For example, if no applications can be opened.

Tip: If the issue began right after you performed a Mac OS X re-installation (excluding erase-installation), seeApplications don't work after reinstalling Mac OS X.

The first and easiest test to try is to see if the issue affects a different user account on your Mac. Each user account has customized preferences and other items stored in its home directory. You'll first need to create an additional user if one does not already exist (follow steps a-h below). Then, log out of the current user and test the issue in the new user account.If this resolves the issue, there may be an issue with a file in the home directory of the original user account.

1. From the Apple menu, choose System Preferences.
2. From the View menu, choose Accounts (or choose Users if using Mac OS X v10.2 or earlier).
3. Click "+" (or click New User if using Mac OS X v10.2 or earlier).
4. Give the new user a name and short name.
5. Mac OS X v10.3 or earlier only: Click the Password tab, and give the user a password.
6. Mac OS X v10.3 or earlier only: Click Security.
7. Select the checkbox for "Allow user to administer this computer". This makes the user account an administrator.
8. Click OK, or quit System Preferences.

There is additional troubleshooting in the article as well but this will get you started.

Thank you for using Apple Support Communities.

All the very best,

Sterling