No Net after virus infection

Even after a virus has been removed, you may have trouble accessing the Internet, as the virus makes permanent changes to the components of Windows that help you to go online. Here are 4 steps you can take to get your internet connection back up and going.  All 4 methods do different things so if one does not work you can move onto the next.

Method 1

Uncheck the proxy usage box in Internet Explorer. Some viruses will redirect your computer to proxy servers in order to perform malicious tasks. You may need to reset these settings after the virus has been removed. In order to do this, open Internet Explorer, then go to Tools->Internet Options. In this dialog box, choose Connection Settings tab. Here click on the LAN Settings button.
This will have two main checkboxes, one to detect internet settings automatically and another to user a Proxy server. Make sure that the Proxy server checkbox is unchecked. Hit OK in this dialog box and in the internet options dialog box as well, and your proxy settings will be turned off.

Method 2

The next solution you could try to get yourself back online is to reset the settings of Internet Explorer, which is your web browser. Viruses tend to change its settings in order to redirect you to malicious websites, and therefore it helps to reset these settings. Resetting Internet Explorer settings will practically give you a fresh copy of Internet Explorer on your computer. The basic method to manually reset Internet Explorer is:
•    Exit all programs, including Internet Explorer
•    Hold WinKey + R, and in the dialog box, type inetcpl.cpl and click ok
•    Click on the Advanced Tab
•    Under Resent Internet Explorer Settings, click Reset, and then click Reset again
•    Once the resetting is complete, close the dialog box and restart Internet Explorer
Alternatively you could just open up IE and under the Tools Menu select Internet Options, Then select the Advanced Tab and select the Reset button.

Method 3

Another solution that you could attempt to do is to reset the Windows Hosts File. The Windows Hosts File contains mappings of websites to IP addresses on the Internet. Windows uses this to redirect the web browser to the correct website on the Internet. However, some viruses tend to edit the Windows Hosts File so that you get redirected to malicious websites whenever you attempt to browse the internet. Therefore if you have no internet after virus infection, you should attempt to reset the Windows Hosts Files as well. This can be done as follows:
•    Hold WinKey + R, and in the dialog box, type %systemroot%System32driversetc, and click OK.
•    Rename the hosts file to hosts.bak
•    Create a new default hosts file by right-clicking on an open space in the %WinDir%System32driversetc folder, pointing to New, and clicking Text Document typing hosts, and pressing Enter.
•    Open the newly created file in a text editor, and enter the following code:
# Copyright (c) 1993-1999 Microsoft Corp.
#
# This is a sample HOSTS file used by Microsoft TCP/IP for Windows.
#
# This file contains the mappings of IP addresses to host names. Each
# entry should be kept on an individual line. The IP address should
# be placed in the first column followed by the corresponding host name.
# The IP address and the host name should be separated by at least one
# space.
#
# Additionally, comments (such as these) may be inserted on individual
# lines or following the machine name denoted by a '#' symbol.
#
# For example:
#
#      102.54.94.97     rhino.acme.com          # source server
#       38.25.63.10     x.acme.com              # x client host
127.0.0.1       localhost
Save the file as hosts in the above folder destination.

Method 4

The first thing you could do is to use Winsock to clean up your internet connection settings. This free software application can be downloaded easily on many websites and will fix any problems with Windows Sockets or with the Windows Registry which might be causing network problems with your computer. It also contains the option of backing up the registry before attempting to fix it, therefore you are secure in case any mistake occurs.
XP Users can download the software at : http://majorgeeks.com/WinSock_XP_Fix_d4372.html
Win 7 users and Vista users have to do this manually:  Here is how
1. Open up the command line utility and enter:
netsh winsock reset catalog (resets winsock entries)
netsh int ip reset reset.log hit (resets TCP/IP stack)
2. Reboot your PC