Well if you dont want to do a secure erase (i can understand your concerns) you can always remove every other hdd (temporarily) from your system and re install your windows from scratch, you will probably need to go into advance mode on the first steps of the install so that you can delete all the other partitions and make only one (ok MS will also make one more that will be 100MB).
If you have another boot hdd on your system you can always boot from that drive and use windows disc management tool to make a single partition on your SSD and re install windows.
BTW how much ram do you have? It might sound crazy asking this but if you have 8GB ram or hibernate files and pagefile can take almost 16GB from your drive.
A good thing to do is to put your pagefile on your mechanical drive, it will save some space, and a lot of pointless read.writes.