DNS (Domain Name System), is the service which translates between Internet names and Internet addresses.

The Domain Name System is one of the foundations of the internet. It is the system that allows the translation of human-readable domain names into machines-readable IP addresses and the reverse translation of IP addresses into domain names.

When you surf on net the dns records will be cache inside your pc. This methods will make your browsing much faster because you wont need to resolve the dns each time you surf a site or network. But sometimes caching can be an issue when certain network change their ip address. You can resolve this by clearing or flushing the dns. Here a few simple command on how to flush your dns cache in PC, Mac & *nix operating systems.

Windows PC

Start > Run > ipconfig /flushdns

Mac

Open Console lookupd -flushcache

Linux

restart nscd daemon.
Open Console /etc/rc.d/init.d/nscd restart

Stop dnscache via Windows services

For windows, If you are having frequent issue with dns caching you can disabled the dns-client caching services with

• Start > Run net stop dnscache
• or manually stopping the services via services.msc (microsoft services console).
  sc servername stop dnscache

The safest way to clean any kind of windows virus is to work in different environment others than its originating operating system. Try virtual Ubuntu (Debian Linux) with Wubi Installer.
Here’s what wubi-installer.org has to says

Wubi is an unofficial Ubuntu installer for Windows users that will bring you into the Linux world with a single click. Wubi allows you to install and uninstall Ubuntu as any other application. If you heard about Linux and Ubuntu, if you wanted to try them but you were afraid, this is for you.

• Wubi is safe - It does not require you to modify the partitions of your PC, or to use a different bootloader.
• Wubi is Simple - Just run the installer, no need to burn a CD.
• Wubi is Discrete - Wubi keeps most of the files in one folder, and If you do not like, you can simply uninstall it.
• Wubi is Free - Wubi (like Ubuntu) is free as in beer and as in freedom. You will get this part later on, the important thing now is that it cost absolutely nothing, it is our gift to you…

Wubi installer.

Wubi wont break your system partition or replaced you windows. You can also installed wubi in any drive and its come with clean Windows uninstaller. You can dowload Wubi at wubi-installer.org or Sourceforge. ~ suggested by ChaosKaizer