I used a mac to program my experiment, but the experiment will actually be run on a PC. The experiment was somewhat complicated and involved several layered screens. I needed to have text (in two colors) in the background throughout, and then have text displayed briefly, followed by images. In order to do this, I programed superlab so that the text that needed to to be in the background was displayed first and ended immediately. In the next events, I unchecked the box to erase the screen. I then had an event for the text prime programmed so that it the stimulus would be erased at the end of the event. I did the same thing with the image. This worked great on my mac. However, when I ran the experiment on a PC, it seems like the text/images were not erasing properly as instructed. A black box covered up part of the next stimulus once I got to the end of the trial. The only work-around I could find on a PC was to erase the screen at the end of the trial, which I do not want to do as it causes the background text to flash. Does anyone have any suggestions? Why is this problem occurring on a PC only? It seems like there is an issue of text-box transparency on a PC and improper stimulus erasure.