Step 3, reload your files from that backup you were keeping. You were backing up, rite?
If this says anything, it's PC FTW. It's the only one that can be reasonably serviced at home with minimal cost, and hazard, provided you take very simple preparation steps.
On a related note, Windows: Partition HDD. Install to new partition. Take salvageable files from old partition and install to new. Delete old partition. BACK UP FILES THIS TIME.