did you consider breaking the folder in two smaller ones? create picfolder2 and MOVE (don't copy) half of pictures there .

use this: winrar utility to compress your files - it works better and has higher compression rate (free)

MP3s : just back them up to CDs or DVDs (which will hold much more - if you have DVD writer). what you can actualy listen to on your CD player - depends on the CD player itself - some will play MP3s (not that expensive to buy either) but older ones will not.

there are freeshare utilities you can find to convert MP3s to other formats ... I will look if I can find it - and post here if I do

if i was you - i would back up all i dont want to loose and than reformat PC - doing that occasionaly, does prolong its usability ;P

good luck