I think my computer is breaking, and I have no idea what to do about it

[Faerie]

When no one else has any lag going on, my tells can sometimes be delayed for literal minutes at a time. Also affected: spells. I can start a spell, and not have it start until minutes after I cast it. Sometimes NPCs sneak up on me, and I die to them even though I have sow and should be able to outrun them.

My graphics have been bugging out, too. The screen will turn white, in... lines originating at a point? That point usually being a character/NPC model.

What's going on?