Your windows dvd can be used to do a clean install
Just keep your activation code available.
If you no longer have either, you can download a windows 7 iso to dvd. Just be careful it does not come from a malware infested site.
If you don't know your product/activation code, run a free app called "magical jellybean keyfinder"
I have a spare ssd and I clone my "C" drive to it as a backup.
I know it will work since I can test it without risking the source.