scr621

Out of the blue my wlm has stopped working correctly. I can see all my emails in my Comcast & Hotmail accounts (the subject line) but when I try to open them I get an error message saying: 'There is an error opening this message & that's' it!
I also noticed that the following options are greyed out (not available) Reply Reply All Forward.
I'm not sure what's going on but it's been like this for 2 days & for a brief moment I was actually able to open & read an email today.
Can anyone help please? I don't know what infomation about my PC to post but I'm sure whoever answers this will let me know.

Windows Vista Ultimate 32 bit
Windows Live Mail version 2009 Build: (14.0.8064.0206)

Thanx in advance for any help