Your save files should be in My Docs > Documents > Games > F1 (something like that for Win7)
Maybe not an option if you need to refresh your o/s, but I would take an image copy of your windows (built into Win7) and use that to restore your system.
If your F1 install is on a different partition, then you wont need to do anything with that, and your F1 saves will be restored from the image.
Thats what I did when I replaced my o/s SSD anyway and it worked perfectly.