By names you mean Windows Live IDs right? Sometimes when I sign in with one of my many (13) email addresses other than the one which is my main one, I'll lose the backgrounds of everything so then I have to go and delete all the caches and reinstall the backgrounds yatta yatta yatta. And when you say "I open both names" do you mean you run polygamy and open two WLMs at once? Or are you opening a Windows Messenger and a Windows Live Messenger at once.
I could've either asked all that, or gone simple like patchou and say...screenshot please.
EDIT:
Ok so you got a screenshot. If you click the help button up the top of the forums and read that, it will tell you how to insert images. You don't actually need to read it though. Just go to
http://imageshack.us and upload the image there. It will tell you what you need to copy into the post you send to upload it.