If there's no VGA (analog) input on the TV, then you'll need a graphics card with a digital output. Whether that output is DVI or HDMI doesn't really matter, as either one can be converted to the other format with no signal loss or degradation. It would, however, be easiest to use a GPU that has the same output connector as the TV's available input. (This likely means HDMI.) After that, all you need is the appropriate cable (and an appropriate converter dongle, if necessary).