Question about Outlook Express (OT)

[Carrie]

I guess this is OT but I get the newsgroup IN Outlook Express.
A few days ago I put in Google Chrome, which seemed faster and easier in
some ways, but I didn't like it for other reasons and took it out and went
back to I.E.
I don't know if that is related, but since then, when my computer has been
shut down and put back on, when I come in to O.E. a box comes up saying
"Outlook Experess is not your default mail, do you want it to be?" The
first time (before I did anything) I went to internet options and looked and
it said O.E. IS my default mail.
But, I clicked YES to make it this.
In O.E. account and options it shows it is my default mail.
Everytime I put the computer on again (I shut it down if I go out and also
ovenight) this box comes up now say ing it's not my default mail and do I
want it to be. And "always ask this if it's not". Well if it's not, what is?
My only other mail is yahoo, and you have to download something to set THAT
as default email.
Anyone know what this might be from and how to fix it?