Michigan was forbidden to hold its primary before Super Tuesday, which it nevertheless did, thus being stripped of all delegates by the DNC.
Obama, therefore, didn't have his name put on the ballot and hence didn't campaign there.
Hillary, however, was electable and visited that state and hence won it by 15%
The results were:
Hillary Clinton 54.61%
Uncommited 39.61%
Dennis Kucinich 3.61%
Now that we all know that Clinton was surprisingly upset twice in that state, who do you think would have won Michigan in 2008 if the primary had been carried out in a normal way (on the same day)?