Receiving e-mai but can,t send e-mail.

When I go to create a new email I get the following message:

A problem occurred while trying to open this message.

I press ok

I get next message:

A problem has occurred. Please try again

Repeats message continuiously.

If I go to a past e-mail and try to reply to it I get following message:

An error occurred replying to or forwarding this message.

Stuck...can't send e-mails from Live Mail

What is wrong?

Just happened a week or so back.