You can connect a laptop or computer with a VGA port to the projector but you will need to purchase a VGA to HDMI signal converter (sold separately). A VGA to HDMI signal converter will accept the VGA analog signal from your computer and will translate this signal into the digital HDMI output signal required by the projector.
If you are having issues connecting with this setup, first double check that your are using the correct type of connector. Is the converter you are using a VGA to HDMI converter or an HDMI to VGA converter? This connection requires a VGA to HDMI converter – accepts VGA input and provides HDMI output.