Hello Ashok,
Welcome to Microsoft Community Forum. Let me ask you a few questions in order to understand and help you better.
1. Did you make any specific change in the computer?
Method 1: The issue seems to occur on computers that have Windows Firewall disabled. Windows Firewall service has to be running even if you’re using another antivirus/firewall program on your computer.
I’d recommend you to check for the status of the “Windows Firewall” service and set it to “Automatic”. Follow these steps:
a. Click “Start”.
b. Type “services.msc” in the Start search box and hit “Enter”.
c. Right-click “Windows Firewall” and click “Properties”.
d. In the “General” tab, select “Automatic” under the “Startup type”.
e. Click "Start" to start the service. f. Click “Apply” and “OK”. Restart the computer and check if the issue gets fixed.
Method 2: You may try to check all the services that run Internet Connection Sharing (ICS) and check.
1. Click Start, Run, type services.msc, and click OK.
2. To enable a service, find it in the right pane and double-click its entry.
3. Be sure its Startup Type is set to Automatic and click OK.
All the following services must be thus configured in order to use ICS:
Application Layer Gateway Service
Network Connections
Network Location Awareness (NLA)
Plug And Play
Remote Access Auto Connection Manager
Remote Access Connection Manager
Remote Procedure Call (RPC)
Telephony
After verifying and/or configuring Automatic startup for each of these services, close the Services window and restart the computer before attempting again to enable ICS.
Method 3: Error could be caused by your security software blocking Internet access/sharing. I suggest you disable all security software and check if the issue persists.
Refer to the article:
Disable antivirus software
http://windows.microsoft.com/en-in/windows/disable-antivirus-software#1TC=windows-7
When you disable Antivirus: Antivirus software can help protect your computer against viruses and other security threats. In most cases, you shouldn't disable your antivirus software. If you have to temporarily disable it to install
other software, you should re-enable it as soon as you're done. If you're connected to the Internet or a network while your antivirus software is disabled, your computer is vulnerable to attacks.
Method 4: You may also try to reset TCP/IP and check if it helps:
How to reset Internet Protocol (TCP/IP)
http://support.microsoft.com/kb/299357
For more reference: Using ICS (Internet Connection Sharing)
http://windows.microsoft.com/en-us/windows7/Using-ICS-Internet-Connection-Sharing
http://windows.microsoft.com/en-US/windows7/Change-Internet-settings-for-ICS-Internet-Connection-Sharing
Let us know the result, we'll be glad to assist you further.
Thank you