Hello Arijit,
- What is the make and model of the computer?
- What is the status of sound device in device manager?
To check status of sound device follow steps below:
->Click Start, and then click Control Panel.
->Click System and Maintenance, click System, and then clickDevice Manager.
Note If Control Panel is in Classic View, double-clickSystem, and then click Device Manager.
If you are prompted for an administrator password or for a confirmation, type the password, or clickAllow.
-> In Device Manager, double click to expand "Sound device", right click on sound device, click "Uninstall" and click "OK".
Check if at all there is an exclamation mark along the driver, it suggests issues with the driver installed.
Incase the drivers does not get installed. You may have to update from manufacturers website.
Also refer to link below:
Update a driver for hardware that isn't working properly http://windows.microsoft.com/en-us/windows7/Update-a-driver-for-hardware-that-isnt-working-properly
Please post back the results. So as to further assist you.