The best way to get XAMPP portable is not necessarily the shortest.  That is because there is a very useful tool out there which you might want to consider.  Portableapps.com is a free package which lets you run applications on an external drive under Windows.  That means that you can not only have your server on the external drive but your editor, most common browsers and other software as well.  Then you can develop pages (and do other stuff) wherever you are and whatever Windows computer you are running on.  You can take your work and your settings with you.

Another advantage is that you can normally install these applications even on a networked computer where you do not have permissions to install normal programs.

Assuming you have a drive (even a 5GB drive would probably do it for just the basics but 250GB or more would be better) do this:

  1. first download and install the portableapps.com platform to your external drive
  2. run the Start program which is now on your external drive and a menu should appear
  3. click on Apps, hover over Get more apps and click on by title
  4. wait a while then scroll down to XAMPP Launcher near the bottom - tick it and press Next
  5. next you need to download either:
    1. XAMPP for PortableApps
    2. the latest version of XAMPP
    3. find XAMPP for Windows and click on More downloads
    4. then XAMPP for Windows
    5. find the latest version 5 (e.g. 5.6.31) but not v7 (7 will be used in the future but until it is widely accepted stick with 5)
    6. Look for the zip file in the list (e.g. xampp-win32-5.6.31-0-VC11.zip) and download it
    7. open the folder where the downloaded file was saved and unzip/extract it
    8. depending how you unzipped the file you may have a folder with a long file name starting xampp-win32 and if you do go into it (if not then you should just have one called xampp or xampplite which is good)
  6. then either:
    1. for PortableApps.com move the xampp or xampplite folder you can now see onto your external hard drive inside the folder called PortableApps\XAMPP\App
    2. not using PortableApps place the folder where you want it
  7. go into the xampp or xampplite folder and run the setup_xampp.bat file following the onscreen instructions and using keyboard commands
  8. either:
    1. go to the PortableApps menu and start XAMPP from it
    2. or go to the folder and start the one called XAMPP_start
  9. you should see a control panel which allows you to start and stop Apache (which includes PHP) and the database server
  10. start the top two (Apache and MySQL) and if they go green all is well (if not you did something wrong so time to start again and maybe do some research to find out what)
  11. you can now use the server as explained soon
  12. now that you are finished with testing XAMPP you need to manually stop Apache and MySQL and then exit the control panel.  You will also need to exit the PortableApps.com launcher menu before you eject/unplug the portable drive

You might want to now look through the other apps available under PortableApps.com.  They will be much easier to install.  They are also listed on their site.  At least add Notepad++ and maybe some other Web editors to try.  Irfanview is good for quickly cropping and resizing images although it is a little weird.  GIMP is good for more advanced graphics but again takes some learning.  Filezilla is a good and simple FTP program for getting pages to proper servers (not needed for XAMPP).  Now would also be a good time to get some extra browsers to test your pages in and an antivirus program just in case.