I work for Continuum, btw
Your mileage may vary, of course, so I'd say have a backup and give it a try - at least EPD didn't ruin anything for me. I'm pretty sure IPython Notebook on Windows machine is doable with some lib-hunting/building, since I managed to have fully functioning IPython Qt console installed and running perfectly on Win7 right now, and Notebook is just a couple additional requirements away from it.
That said, it's very easy to get it going on EC2, especially with Notebookcloud.
With the latest EPD 7.3-2, ipython notebook --pylab inline works for me on windows 7 32 bits + chrome. Feel free to contact me privately (see my HN account) if you want more help on how to get this fixed.
edit: for clarification, I saw this comment, and three hours later I'm back to reply.