This is my fifth full format and install of Ubuntu in under a month. I finally have my Gnome 3 desktop working again, but again, the Gnome shell themes is not select-able. I have asked the question of how to fix this common issue before, but I have seen no positive resolution. Does anybody know of a simple fix? This is a common issue and I have seen hundreds of postings related to it, but other users only seem to get half-way answers also and it goes unresolved. Would it be advisable to completely purge Gnome desktop and reinstall? If so how would I do this? I cannot use any extensions if the shell is not working, so I am desperately seeking resolution for the issue. Thanks in advance.