Hi L.,
basically I was resolve this very easily... I have two hard discs on one I run OS and another I use only for storage of my files (where I have different folders for pics, music, movies...) simple when I download/copy something I save all that direct on that another disc, so whatever happens with my Windows my files are safe.
You can do same thing also with different partitions.
That is also answer for your second question, simple when you install some new program point them to install on second disc/partition instead of your Program Files part at C: disc.
Hope this will help you, also hope that other SCF Members will take a part in this Topic with theirs suggestions and experiences??
Regards,
S.