I also had the same problem, contacted customer care at Optoma USA...they have confirmed its a fault with VGA cable...now getting a replacement cable

Try jiggling the connecting to the VGA output on your PC

Hi there:
You directed this question at me, but unfortunately this isn't my expertise and I am unable to provide you with a real solution at this time.

Hopefully one of other experts will be able to provide you with a real solution.

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