xlwt and xlutils not working while xlrd works all right

I am a Windows user and I have a Python 2.7 version. I would be really grateful if someone helped me on that: I have downloaded, unpacked with 7Zip and installed xlrd, xlwt and xlutils (the installation seemed to be completed all right) but only xlrd works. Even short commands like from xlwt import * result in an error, e.g.:

Traceback (most recent call last):
  File "C:/Users/fanny/Desktop/python/excel_28.01.w.o.utils.py", line 2, in <module>
    from xlwt import *
  File "C:/Users/fanny/Desktop/python\xlwt.py", line 1, in <module>
    from xlutils.copy import copy
  File "C:\Python27\lib\site-packages\xlutils-1.7.0-py2.7.egg\xlutils\copy.py", line 7, in <module>
    from xlutils.filter import process,XLRDReader,XLWTWriter
  File "C:\Python27\lib\site-packages\xlutils-1.7.0-py2.7.egg\xlutils\filter.py", line 17, in <module>
    from xlwt.Style import default_style
ImportError: No module named Style

What could be the problem?

Copyright Notice：Content Author:「fanny」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/21402075/xlwt-and-xlutils-not-working-while-xlrd-works-all-right