Browsers IE9

how can I tell if NIS 2012 or previous version block my browser my.msn.com/ it worked fine for very long time with WindowsLiveID and for past 3-4 days unable to sign on. I can get WindowsLive messenger and all other sites without a problem. Tried sending to their forums but no replies. Understand they did have a sign in problem a few days ago but claim it is repaired but not for me. tried cleaning out TIFs and Temp files plus rebooting several times. any ideas if NIS may be problem this time