welcome screen will not show

was playing dungeons and dragons online a few days ago and it crashed, now my welcome screen does not show, nor is there any user icons, if i click where mine generally is on the monitor it still lets me log in but its extremely slow and theres image issues (yes this is the same problem as in another post trying retitling to see if i can get some help) when not on safe mode the computer flickers black then comes back and generally moves to a different spot on the screen