DaFlop's dashboard

English is NOT my main spoken language but ill try the best i can :P
I know that this is an old question, but i have a solution...
In win explorer go to:

C:\Users\UserName\AppData\Local\Spotify
copy the folder called Storage
paste it to an USB memorystick (or another folder for backup)
When you need to restore play list, just copy/paste back to
C:\Users\UserName\AppData\Local\Spotify

It works. I have just done it from a windows xp to a new windows 7 installation.

Enjoy!