Hi, my pc was running fine for a couple of months and yesterday my daughter knocked down pc (pc was on the floor it didn't fell from desk or any height just knocked on the side) and i couldn't get it to boot. I tried to take out 1 ram stick and it booted normally. So after couple of minutes swapping ram slots and trying different combinations i saw that all ram slots are working and pc can boot with 16 gigs of ram but only in single channel. When i try to put ram on 1 and 3 or 2 and 4 it wont boot. Any help ?