This sounds like the problems with viewing the calendar using Internet Explorer 8 and earlier.
Since you said that it worked previously, I'm guessing that you are using a version of Internet Explorer after IE8. But it's possible for a later version of IE to get into a mode where it works like those earlier modes. The most obvious possibility is Compatibility View. Make sure that you have turned that off.
Questions that can benefit the larger community should be asked in a public forum, not a private message.