Why did my ASP.NET Web App stop showing AM in times?

I haven't made any code or configuration changes (that I know of) to my ASP.NET web application and this morning it suddenly stopped showing the AM in my displayed times. PM still shows up, just not AM. It's hosted on Windows Server 2003. I figured somehow the OS regional settings might have been changed somehow, but that doesn't appear to be the case. How could this have happened?

I was able to change the OS time format to hh:mm:ss tt and then back to h:mm:ss tt and it seems 开发者_StackOverflowto have fixed my app. I'm going to assume that the hosting company made some kind of change unless somebody has a better idea

Does this show up in the html? I'm wondering if there's something funny in the css that is hiding the AM (if it's in a span) which has only just got to your browser with caching and the like.

The other thing that springs to mind is, have any windows updates been put in recently? I can't think of any that would cause this kind of problem, but you never know.

It sounds like something has changed, these things don't just happen.