Have you got the proper drivers? Have you uninstalled the onboard graphics drivers when installing the video card?
Latest drivers are installed - 18.104.22.16896 (7/9/2010). Onboard graphics drivers are uninstalled - at first they don't show when the NVIDIA card is installed - took NVIDIA card out, uninstalled onboard drivers (they show in System Properties/Hardware/Display Adapters), reinstalled NVIDIA card. Computer is a DELL Dimension E510 Pentium 4, 3 Ghz processor, with 4 GB memory running Windows 7. Since the screen saver pan and zoom works smoothly using a VGA cable I think the computer is fine - just not sure what else would cause the NVIDIA card to process as expected. Please advise.
I'm using a new DVI-I cable with a DVI-I to HDMI converter to the back of the HDTV monitor's HDMI port. All else looks good on the monitor so I think the cable is ok. I've read something about the NVIDIA card accelerator options may not be set right - don't know where this info is and what it should be set at. Please advise if there is something else to check. Thanks for responding to this supposedly simple but aggravating problem that I'm having. I haven't found anything on the NVIDIA nor Windows site that describes this fundamental looking problem.