when I upgraded to IE7 the outlook express button had gone, I now have to go through the 'start' button to get to outlook and my emails.
I don't know if this will work but windows has a 'system restore' function where you can reset you computer to the state it was on set dates in the past month or so. I used this function when I downloaded some malwear that changed my home page and shoved loads of fake 'you have a trogan' pop ups at me, well it worked so this might get back IE6 for you
click on 'start'
then click on 'help and support'
under 'pick a task' select 'undo changes -......-system restore'
and the choose a date that you would like your system to be restored to.