Hello!
i think i have just resolved the problem!
I just found in another forum:
IE7 has made changes to the way that the rendering engine interacts with the
Restricted Sites zone - the end result is that if you are using Outlook (not
2007), have IE7 installed and use HTML as your email format, then when you
type an email the IE rendering engine will check the registry for entries in
IE's Restricted Sites zone **every time you type a character***.
FIXES:
Remove all of those entries in the Restricted Sites Zone - a quick way to do
this is to reset Internet Explorer's settings (Tools, Internet Options,
Advanced tab)
After i had removed all those entries, my Outlook works great again.
regards
Martin
PS: another suggestion worked by another poster: He made the "Outlook - Today -side" as the starting page and this also resolved the problem.