This site will look much better in a browser that supports web standards, but it is accessible to any browser or Internet device.
Have you emptied your IE cache? That often works.
Make sure notepad.exe is in ..\windows and that it is not a third party version. Also, make sure that there is no shortcut to notepad.exe on your desktop.
Also, search your registry for the DWORD noviewsource. If that exists, delete it or set it to 0.
Have a look at these site for hints:
Cannot View Source in Internet Explorer
Cannot View Source Code for Web Pages