First we know the most useful software thats a file manager name xplore.
You can open zip file,listen music,see vidio.open all data,system file,install software see photo,and much more.so download first this to use other software.
then you use a jbaktaskman software to easy use your phone.u can kill all the aplication,see open aplication.install the aplication and open the aplication first then see.just click sowe time ur left soft key this app will open then.
one of useful app for symbian is coreplayer.it is a vidio player,u can saw hd vidio in normal mobile in this.you can saw tv,youtube video,download vidio.etc.it is important because u can see download failed vidio.
if YOU use a symbian mobile u will know the software name rompachar.it will help u to manege ur symbian mobile fully.also download rompAcTh and open zip file by xplore and copy .rmp file in the c:/paches/exaple.rmp.then open rompachar and click any pach and u see green .if dosen't work then red cross will apear there.there is a lots of paches.download now.
i have a special software for s60v3 version mobile n73.this mobile had a joystick problem.it is too hard to control and playing a game.you can use 2 for up,8 for down,4 for left,6 for right,5 for select.then u don't need to use ur joystick.it is a special app for nokia n73.