Ya I have followed your aequence of steps but the problem still persists with the keyboard...

Look at my edit in the previous post.

You also may have to change the system locale

Without actually seeing your system and how it is set up, it's hard to determine what might be wrong.
But it is definately a software setup issue when Windows was reinstalled.

The system locale determines the default character set (letters, symbols, and numbers) and font used to enter and display information in programs that don't use Unicode. This allows non-Unicode programs to run on your computer using the specified language. You might need to change the default system locale when you install additional display languages on your computer. Selecting a different language for the system locale doesn't affect the language in menus and dialog boxes for Windows or other programs that do use Unicode.

Click to open Region and Language.

Click the Administrative tab, and then, under Language for non-Unicode programs, click Change system locale.  If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

Select the language, and then click OK.

To restart your computer, click Restart now.

Check your keyboard layout and make sure that it is set for the proper location.

EDIT:  Forgot to put in the steps.

Start > Control Panel > Region and Language
Make sure all of the settings are for your area.

Keyboard layout means do u mean physically checking whether the keyboard is placed in the right position? But I dont think that's issue only the problem is with the combination keys, it must be some kind of software glitch, before installing everything was working fine....

Ya I have already done that too but the problem still persists in the same way.

hey thanks alot your info helped me alot man!!!!!

I happy that you got it working.