Black client screen during champ select

This has happened in the past as well but not in ranked queue so it didn't bother me as much but now that I got a black screen in champ select of ranked queue and lost lp I am mad. It was in last pick phase of champ select and I had to pick a champ when my client just went black. I could still see the border of my client with my friends tabs and stuff but no champ select. Please help so that I don't again lose unnecessary LP. Thanx