A clean install moves all your old system folder things to a folder called (I think) Previous System Folder. You can then move things over to the System Folder selectively: open both side by side, move a few things over, restart, and verify that your system works OK. Repeat until you have the stuff you need. I'd recommend keeping the remainder of Previous System Folder around for a while Just In Case. If you have Conflict Catcher, you can use the System Merge feature to help you do this.