have you tried also unticking Other Explorer MRU's and Taskbar Jump Lists.
i know you would think "how are they related?" but I had a similar issue ages ago and unticking those other choices was the key for me.
do you have an entry in the Applications tab for OpenOffice?
My OS is Windows 7
I've just done a clean and disabling what you said I think this has worked, and no there is no OpenOffice in Applications tab on CCleaner, I would have thought this would have been simplist way.