Ok, based on all the information you've given:
You cannot run a "full version" of Windows 7 on a DVD. 1, a full install is too big and, 2, a full version of windows needs to be able to write to it's source, and so a DVD will not work.
If it is completely impossible to boot from a USB disk, and a full install of Windows 7 via DVD is out, you are much more limited in your options, but at least you now have a better idea of what you can and cannot do.
There are Live CD's of Linux and Windows, but if your needs are for .Net and Mono (a Linux-compatible implementation of .Net) will not work, then you need Windows.
Once again, the assumptions are:
- There is no possible way to boot to a USB drive.
- You need .Net and not Mono or any alternatives.
- Windows will not run as a full install from a DVD, both for space and for needing a writable "base" media.
So the only option then is a Live Windows disk with preinstalled .Net components.
If Windows XP is an option, it is a lot easier to fit onto a disk, and .Net (up to Runtime 4 I believe) will run on it and can be installed as part of the Live disk setup. Try PE Builder if this option will work for you: http://www.instantfundas.com/2007/11/how-to-create-windows-xp-live-cd.html
I cannot find an option for Windows 7 live that explicitly states it allows .Net function. Though Windows 7 has .Net implemented by default, so unless it's a specific .Net toolset not included by default, you may find it'll work without needing anything special.
Here's another possibility:
These are instructions on how to boot from a VHD, or Virtual Hard Disk, such as the Windows 8 Developer Preview. Creating a Windows 7 VHD shouldn't be too hard and it should work with your licensing strictures.
If you've got a large enough USB drive, this may be a way around the problems booting from USB. It looks like you could replace the booting from USB steps with booting from a disk, and then mount the VHD stored in the USB drive at the appropriate point in the setup process.