Want to use Windows 7 and 2003 in my computer simultaneously

Want to use Windows 7 and 2003 in my computer simultaneously

First of all, I'd like to clarify what you mean by "simultaneously".  Does it mean :

1.  You want both Windows 2003 and Windows 7 to run at the same time?

or

2. You want to be able to select which Windows version to boot during startup?

If you mean the first one, you will have to install either Windows 2003 or Windows 7 as your main operating system and install a virtual machine where you will install the second OS (operating system).  Virtualbox (https://www.virtualbox.org/) is one such free tool.

If you mean the second one then what you want is to "dual boot".  There are several guides on the net on how to accomplish this.  Assuming you already have Windows 2003 running there are basically 3 steps:

1.  As with all operations involving changes to your hard drive, make sure to back up all important data to a separate drive or optical media.

2.  Create space  for Windows 7.  You could either add a new hard drive or repartition your existing hard drive.  There are free tools out there for repartitioning a hard drive without having to reformat it.

3.  Install Windows 7 to the new hard drive or partition.

We can discuss either option in more detail if you want.  Just post some more.

Hope this helps.