I have to upgrade Magento from 126.96.36.199 to 188.8.131.52 and in that case I cloned the live system to an sub-domain of the live Domain. I always fixed the multi conflict with issue and getting upgraded I thought, but I dont know if it realy worked. Because when I hit the refresh Button after upgraden via Magento connect Manager I got an blank page and when I try to went back to the backend I got an 404 Error and also at the frontend. Every Site is gone into the Magento 404 Page.
I spend hours of time to fix it and try the solves of this threads:
But nothing works for me.
Do anybody knows a fix that I dont try until yet?