The main thing is not have an overnight change over and assume all will be well, best to be slightly paranoid and take time to prepare in a Win7 test environment. Your processes should not need any modification, changes are more likely to come in the object layer. Because the Windows UI is slightly different, you may find some of your xy co-ordinates need adjustment and that your Surface Automation reference images and colours need to be redefined. Depending on they type of application, some elements may need to be re-spied. The main advice is to treat the regression testing as a mini-project and go through one process at a time, the chances are there won't be many changes, but don't naively assume there will be none.
