Kali Linux: Fix Installing & Updating Packages

write in terminal

nano /etc/apt/sources.list

and then replace all text with this

# deb cdrom:[Debian GNU/Linux 7.0 _Kali_ – Official Snapshot i386 LIVE/INSTALL $

# deb cdrom:[Debian GNU/Linux 7.0 _Kali_ – Official Snapshot i386 LIVE/INSTALL $

## Security updates
deb http://http.kali.org/ /kali main contrib non-free
deb http://http.kali.org/ /wheezy main contrib non-free
deb http://http.kali.org/kali kali-dev main contrib non-free
deb http://http.kali.org/kali kali-dev main/debian-installer
deb-src http://http.kali.org/kali kali-dev main contrib non-free
deb http://http.kali.org/kali kali main contrib non-free
deb http://http.kali.org/kali kali main/debian-installer
deb-src http://http.kali.org/kali kali main contrib non-free
deb http://security.kali.org/kali-security kali/updates main contrib non-free
deb-src http://security.kali.org/kali-security kali/updates main contrib non-free

then ctrl+x
press y
press enter

open terminal and write 

sudo apt-get upgrade

press enter

then enter this

sudo apt-get update