How to install more than two versions of visual studio

I am new bee to the world of visual studio and started learning about this technology. I want to know that it is possible to install more than two version of Visual Studio in one computer system or not. I need this explanation because I have the codes of the software which are developed in the previous versions of Visual Studio. Now for studying these codes I need to have both the versions on my computer system.

Yes it is possible to install more than two versions of Visual Studio in one computer system but before that you must have the following things.
1. Once open the Visual Studio .net 2002 solution in the advance version of visual studio whether it is 2003, 2004, 2008 or 2010 the this solution can never be open in the Visual studio .net 2002.
2. If your are trying to open the solution of visual studio .net 2003 in the advance version then it will ask for the upgrade option, and once upgrade the solution then it can not be used in visual studio .net 2003.

I will like to discuss the problem which I have faced while installing the different version of Visual Studio .net. I have installed two versions of Visual Studio in my computer system that was working fine. Just for trying I have un-installed one version from my computer system. This un-installation resulted in the crash of my both the versions of Visual Studio .net. Now I need to know the solution for this problem.

Do not worry about it the solution for this problem is really simple you just have to remap the files associated through Restore File Associations button. You can find this button from the General >> Environment >> Options Dialog Box.
One more thing if you want to install the Visual Studio .net 2008 in your computer system and if you have the previous version of Visual Studio .net 2005. Then it will not repair the .Net framework 2.0 , for repairing this you have to repair .Net framework 2.0 manually. You can do this from Add Remove programs.

It is possible to install different version of Visual Studio .Net on one computer system but there is a conflicting problem with these, which are mentioned below.
1. Visual Studio .Net 2002 works on the .Net frame work with the version of 1.0 and the Visual Studio .Net 2003 works on the .Net frame work with the version of 1.1.
2. Visual Studio .Net 2003 gives the choice of saving the project with the frame work of your choice
3. The same thing cannot be expected with Visual Studio 2005. Projects which are created in Visual Studio 2005 only can be supported by .Net frame work 2.0.
4. Visual Studio 2008 gives you the option for choosing the .Net frame work from the version of 2.0, 3.0 and .Net framework 3.5.
5. So you have to be careful when you are installing more than one version.