Cant join game

Recently i got like an ULTRA low end laptop from the stone age, ive tuned it up so it isnt that bad can run Roblox for a fact but for some reason i cant seem to be able to enter a game so i cant change my settings to low and beyond lower. Please help, im not sure if it even it even is the graphics on my laptop because it loads in and it loads the champion card to 100% then goes black and crashed, i cant seem to join a custom game either (including twisted treeline and the other one) is there anyway i can change my settings out of game? i tried touching on the input file in the config file but it usually crashes since I dont know what to put ( if you could tell me that would be great and like i mean the lowest possible settings) I dont know though it doesnt seem to lag on the client or when loading (Although i end up at 100% about 30 seconds-1 minute after everyone else) (ive only tried this twice though since i didnt want to get a leaver buster)