Windows 7: Cannot share connection with Xbox, Error 5

My laptop won't let me share my internet connection with my Xbox to connect to Xbl. I have a USB modem so when I usually connect,
I connect my ethernet cable to my laptop:
I right click on the connection and go to properties:
click on sharing tab:
check all of the boxes:
then on the drop down bar I select Local area connection
I click OK and it works. When I do it now however, i'll click okay and it'll say "Error 5 Access Denied" I'm the administrator or my laptop so i don't see why I can't do this. Also I try to do it the other way around by going to Local A connection and sharing it'll say sharing has been disabled by network administrator.

If you can understand all of this stuff plz help all answers will be appreciated.