Nothing works trying to download programs?

[mahesh]

I tried downloading two programs. MPC HC (Media Player Classic Home Cinema) and REW (room equalizer wizard) and I can not get permission to install them. I have permission to open Chrome and I can use su in the terminal to access that. But if I go to software it will not give me permission and files will not let me save. I have been trying things for days trying to solve this with searching for solutions. Otherwise Ubuntu works for me. I would hate to abandon Ubuntu because of these issues. Any suggestions that do not need a professional to solve?
Thanks, Deron.