he Network Simulator-2 is coded to work on Linux. If you want to run the ns2 softaware on Windows (which is not recommended) you need to have Cygwin installed on your Windows for further information refer the below links:
Note:The Cygwin version of NS2 has a lot of bugs and there is a very little support available for it. It is better to have NS2 installed on Linux.
There are many flavours of Linux avaialble. I am using FEDORA-an open source version of Linux from Red Hat. You can download the new version of FEDORA form the below link
Installing FEDORA is very easy. You can also dual boot FEDORA with your existing Window s Operating Systems.
If you are planning to remove your Windows OS and install FEDORA then follow the step by step instructions in the below link
If you do not want to remove the Windows OS and planning to Dual Boot WinXP and FEDORA (as I have done) you need to follow the below link
If you are having a low capacity hard-disk(<=20 GB) then it is better to use VMware to dual boot Windows and FEDORA. There is a good video tutorial which illustrates how to install VMware o Windows, I have provided a link to that tutorial below http://showmedo.com/videos/video?name=linuxDevijverVMWare1&fromSeriesID=38
After installing VMware you can install the FEDORA in normal way.
After installing FEDORA we move to the next step-installing the Network Simulator-2 package.