If you havnmt already consult the manual as hat will be the best place to find out how as the removal of the I/O should DEFINETLY be there.
as for the raisers, they are little cylender looking things that go onto the inside of the case so that the MOBO isnt touching the side of the case = shorts.
Line them up with the holes on the motherboad and make sure there are no others on there as they will be touching mobo which will give shorts
Pics could help us help you alot easier