That LSD trippy behavior was something I started seeing on my 8800GTX before replacing it. I had attributed it to potentially failing hardware, but it's also possible it's just overheating. Although you'd think it wouldn't wait 3 hours to do that.

updated the OP with a list of things to do.

@Tommy_H - Do you run your fan at max speed? Might be a good way to determine if you have an issue generated by heat, or something else.

Closed for post limit.