Next weekend, I will be doing my half-yearly format. My e-mail, documents, backups etc. are always saved to my d: drive. What I do is drag them to c:, format d:, drag them back to the now clean d: and finally format c:.
It has just occurred to me that I could save my self a bit of faffing by copying my Dial Up Networking folder over to the clean d: before formatting c: and then replacing the empty DUN folder with my copy after I have re-installed Windows .
Would this work?