Our first recommendation at this point would be to skip the receiver and connect your computer directly to your devices.
Also, ensure that you are running the latest driver version:
If the problem persists, please let us know exactly the model of the devices that you are using and the connection that you made.
Thank you for the answer. Unfortunately, I cannot output directly to my devices, as the receiver processes audio. That is, I'm using the HDMI connection to the receiver to process 7 channel audio. For instance, I insert a Bluray (or DVD) into my computer (or watch TV recorded via windows media center), and both the audio and video are sent to my receiver via HDMI. The receiver plays the 2, 5, or 7 channel audio, and video is passed (by the receiver) to my projector. It's a Denon receiver, but I cannot remember the model right now (at work). So, I cannot bypass the receiver.
I have checked that website previously and all my drivers are up to date.
If I am outputting to both the projector and my computer monitor, everything works fine. If I run the receiver without the projector being on, then everything goes haywire. I have an interim solution, which is to use a manual HDMI switching device (two inputs and one output). I connect the computer to the receiver using one input of the HDMI switching device for when I want to watch bluray/DVD/TV. Once I'm done watching, I switch the HDMI switching device to the second input, which has nothing on it. (Thus, the computer is no longer connected to the receiver via HDMI.) I can then turn on the receiver to listen to music. However, this is less than ideal for getting my wife and kids to be able to use the system.