Install Fiji on Windows
Fiji comes as a portable application. That means that you do not have to install it; just download, unpack and start it.
First, go to Fiji's home page:
After clicking on the Downloads link, select the appropriate .zip file:
When asked, you can tell the web browser to open the file right away:
Now, select Extract All... from the File menu of the window which just popped up:
The extraction wizard will ask you for a destination on the second page; you should not use the default (which is a temporary directory), but select something like Desktop instead:
At the end, the extraction wizard will ask you if it should open the directory which contains the extracted files. Say yes, and open the extracted directory Fiji.app:
You can start Fiji by double-clicking on the fiji-win32 executable (on 64-bit systems, it is fiji-win64).
Next time you want to start Fiji, just open the Fiji.app directory on your desktop and double-click on the executable. To make things easier, you might want to create a shortcut to that executable and put it on the Desktop, into the Start menu, or into the QuickLaunch bar.