My game slowly corrupting itself please help

[jaunty condor]

So whenever i turn on the flashlight or a lamp my game goes from 60fps to 1 the game is making those hitch pitched noises when it's like missing audio and I tried playing the half-life and it just gets worse and worse the lighting broke like some spots are lit some are dark its just out offhand

and yes i did try verifing integrety and sutch but its not helping