My software center suddenly not working. When i tried to open it from the launcher, its only loading but showing nothing.

I tried to run it from terminal, and got this error :

Traceback (most recent call last):
  File "/usr/bin/software-center", line 36, in <module>
    from softwarecenter.utils import (
  File "/usr/share/software-center/softwarecenter/utils.py", line 19, in <module>
    import dbus
  File "/usr/lib/python2.7/dist-packages/dbus/__init__.py", line 103, in <module>
    from dbus._dbus import Bus, SystemBus, SessionBus, StarterBus
  File "/usr/lib/python2.7/dist-packages/dbus/_dbus.py", line 39, in <module>
    from dbus.bus import BusConnection
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 39, in <module>
    from dbus.connection import Connection
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 37, in <module>
    from dbus.proxies import ProxyObject
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 34, in <module>
    from dbus._expat_introspect_parser import process_introspection_data
  File "/usr/lib/python2.7/dist-packages/dbus/_expat_introspect_parser.py", line 26, in <module>
    from xml.parsers.expat import ParserCreate
  File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module>
    from pyexpat import *
ImportError: /usr/lib/python2.7/lib-dynload/pyexpat.x86_64-linux-gnu.so: undefined symbol: XML_SetHashSalt
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 63, in apport_excepthook
    from apport.fileutils import likely_packaged, get_recent_crashes
  File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 5, in <module>
    from apport.report import Report
  File "/usr/lib/python2.7/dist-packages/apport/report.py", line 16, in <module>
    from xml.parsers.expat import ExpatError
  File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module>
    from pyexpat import *
ImportError: /usr/lib/python2.7/lib-dynload/pyexpat.x86_64-linux-gnu.so: undefined symbol: XML_SetHashSalt

Original exception was:
Traceback (most recent call last):
  File "/usr/bin/software-center", line 36, in <module>
    from softwarecenter.utils import (
  File "/usr/share/software-center/softwarecenter/utils.py", line 19, in <module>
    import dbus
  File "/usr/lib/python2.7/dist-packages/dbus/__init__.py", line 103, in <module>
    from dbus._dbus import Bus, SystemBus, SessionBus, StarterBus
  File "/usr/lib/python2.7/dist-packages/dbus/_dbus.py", line 39, in <module>
    from dbus.bus import BusConnection
  File "/usr/lib/python2.7/dist-packages/dbus/bus.py", line 39, in <module>
    from dbus.connection import Connection
  File "/usr/lib/python2.7/dist-packages/dbus/connection.py", line 37, in <module>
    from dbus.proxies import ProxyObject
  File "/usr/lib/python2.7/dist-packages/dbus/proxies.py", line 34, in <module>
    from dbus._expat_introspect_parser import process_introspection_data
  File "/usr/lib/python2.7/dist-packages/dbus/_expat_introspect_parser.py", line 26, in <module>
    from xml.parsers.expat import ParserCreate
  File "/usr/lib/python2.7/xml/parsers/expat.py", line 4, in <module>
    from pyexpat import *
ImportError: /usr/lib/python2.7/lib-dynload/pyexpat.x86_64-linux-gnu.so: undefined symbol: XML_SetHashSalt

If i remember correctly, i dont do anything with python library. I did some googling and people said to do apt-get update & upgrade. I tried them, but no luck.

UPDATE

I tried to reinstall python & software-center using :

sudo apt-get install --reinstall python2.7
sudo apt-get install --reinstall software-center

But the error still persists

Thanks for your time.