Is this the only mail address that you use in Windows Mail or do you have others that work.
I had a slightly different problem about 2 weeks ago,There was an update for Windows Live Essentials which I let update,After that my E-mail program would not work.I use Windows Live mail so may be a different problem than yours.
The only way to get mine to work again was to remove Windows live essentials and download it again using File Hippo.It worked with no problem after that but maybe it was the older version that was downloaded.
Like I say not sure if Windows mail is the same as Windows Live mail or not.
If it does not come bundled with Windows live essentials just ignore this.