Thank you for posting and thank you for testing this with another computer already. Does the projector also display the dotted lines when no computer is connected, just the blank projector image on it’s own? Are you able to check if the projector lens has any markings on it that might have been caused by cleaning? Only do this when the projector is turned off and cooled down, you do not want to blind or burn yourself!
The best thing to do if you can find no marks and the image is fine if no computer is connected, is to find the serial number printed on the project and call up our Tech Support so we can process the next steps for you.
Please quote your reference for this problem: 00464559