HDMI out doesn't work on Windows, VGA does. Both work on Ubuntu.

[saihv]

Hi, I'm experiencing a strange problem all of a sudden. My monitor, which has Intel Graphics HD 4600 and an Nvidia GT750M running with Optimus, has stopped recognizing anything connected ro the HDMI port. The monitor/tv doesn't appear in device manager, nor in the personalization screen of my Windows 8.1. Connecting the display to the VGA port works, and HDMI works in Ubuntu. I tried reinstalling the Nvidia driver (even tried a different version), nothing changed. I'm doing a system restore as I am.typing this. Can anyone help me out with suggestions or possible fixes? Because it works in Ubuntu, I'm sure it must be a software issue, but I'm still worried. Thanks!