I guess that you are obscurely asking how to get a Dosbox build that already includes Windows 95, but I'll answer your question as is 😉
The "real hardware" way:
Microsoft have tools to prepare "preinstalled" images of Windows. On recent Windows, it's called sysprep. Please note that sysprep didn't exist on Windows 95, but I'm sure that it had their own tools to do the task (maybe found on Windows 95 Resource Kit). Also, there are tools to make your own "distribution" of Windows (like those Recovery CDs from HP, Fujitsu and other marks) that run a customized installation of Windows that includes their own drivers.
The basics principles of sysprep are:
- You got your empty computer.
- You install Windows and everything that you need into your image.
- You run sysprep to "clean" the installation and turn off the computer.
- You clone your installed disk from computer to computer (using tools like Clonezilla, Acronis True Image or Norton Ghost).
On every computer you clone that installation, you will be asked the customization options but everything will be installed.
The emulation way:
You don't really need to run sysprep or other tools, because you could copy the disk image file from computer to computer (as you may do with virtual machines on VMWare or Virtualbox). The new copy won't need everything to be installed, so you could pass it to your friends.
Downloadable preinstalled images?
Fine. I've seen one of those lately (Windows 98) but they're illegal. Don't ask for it. Almost everything that comes from Microsoft is protected by copyright laws, so you shouldn't be able to get it.
I have traveled across the universe and through the years to find Her.
Sometimes going all the way is just a start...
I'm selling some stuff!