Internet Explorer is a lousy browser, which is prone to many problems which can be extremely hard to rectify. The simplest solution would be to use a better browser. Nearly all of the 'regulars', here in AB's 'Technology' section, use Firefox.
Download Firefox
http://www.mozilla-europe.org/en/firefox/
and install it.
Then use it to log into your email account at
http://bt.yahoo.com
and you should be able to view your mail without any further crashes.
(Thereafter, always use Firefox for your web browsing. You'll find it much better than Internet Explorer).
Chris