hello. installed first linux system - ubuntu 12.04 lts, , installed gnome-shell it. when started using it, noticed animation of windows' movement slow , not smooth. more specific, situations in problem occurs when drag windows across screen, or when press , unpress activities button. have intel e6600 cpu, 2 gigs of ddr3 ram, , ati radeon hd 4830 graphics card. started reading in forums similar problems , found promising soulution - add line "export clutter_vblank=none" file /etc/environment. when tried save file after editing it, didn't allow me. didn't allow me save file. checked file's properties in "permissions" section, , says owner of file "root", , i'm not allowed change it. of course logged in account (the account), , not guest account or something. i'm new linux , don't understand how stuff works. how edit line file , save it?? please me. in li...