installing software

I let a friend use my Toshiba laptop and he uninstalled my Microsoft office 2013 and some other programs without permission and went into the registry and messed around and when I tried sys restore I found he shut it off.I tried reinstalling the software but I get an error message! is there anyway you can help
me restore the registry settings so I can reinstall my programs ?
My laptop s a Toshiba L755-S5245