I was making a rather long picture, about 200x2000 px. I went to add text, (12 pt courier TI if that makes a difference), and I messed it up so I clicked the " (/)" button to delete modifications. The layers then disappeared and I could not complete any more actions due to a program error. Then it stopped working, asked if I wanted to wait for a solution, etc. I happens every time I try it. There are no other layers besides the background and text layer, and nothing drawn in yet. I thought it might be to do with the size (even though it usually handles 2000 px fine) so I reduced it to a quarter of that size but still the same thing. The resolution is just 72 dpi. Trying different fonts and sizes yields the same result, and I have almost no other applications running besides this. Any idea how to fix?
We can't know. You have not provided any system info or other technical details like the actual crash logs or what exactly you are doing with your text. From the looks of it you are simply having hardware acceleration issues and/ or a bad font that messes with the font system, so turn off hardware accel in the prefs and check your fonts.