After Uninstalling Gnome3, i reboot computer and appeared Proxy user below mine and didn't know its pass. After i logged in with my name, terminal just opened. Then i tried installing ubuntu desktop but it couldn't fetch repos so i couldn't. I updated the sources.list and removed old 10.10 ones but it didn't work also, cause i couldn't connect the internet due to proxy i guess. I tried many solutions similar to mine. But i couldn't solve it. I hope they didn't effect the system badly. I just want to know,
Is there any way to fix up the system without reinstalling Ubuntu or without loss of user data?