Why have I had to change my Username?

Log out and try logging in again as ExD. It sounds like ExD and ExDancer are 2 completely different users.

I had the same problem on mumsnet.
Can`t be bothered with it anymore,stick to Gransnett.

My change of name was because of a technical glitch. I got to the stage where I’d rather stick pins in my eyes than sort it.
So it was easier to change name.

No, I was always ExD.
I've lost data on the 'Private Message' and the "I'm On' pages too (not that it matters, just thought it was worth mentioning).

In order to log in to Gransnet as ExDancer you d have to have registered with that name with Gransnet. Nothing to do with Windows or Microsoft. I’m sure I’ve seen you posting as ExD over the last few days though, perhaps Gransnet HQ will be able to help explain what has happened. Does someone else in your household have access to your device?

Possibly EXD isn’t a long enough username?
If you were Exdancer at some stage before maybe they just reverted back as it has more letters in it?

How strange! Were you ExDancer before?