Another Way To Connect Computer to og TV Other than S-Video?

I am trying to stream Netflix on my TV. I have an old og TV. It only has a coax/cable connection - no other connections. I use an RF modulator to hook up the TV to the DVD/VCR. I have an S-video cable running from the desk top computer to the RF Modulator to the TV. The picture that comes across to the TV, from the computer is way too large for the TV and overlaps greatly at all sides. I am told the Roku box will not work with my TV because I do not have a direct connection on my set, the connection has to run through the modulator. I would prefer to be able to run cables from my computer without a device like Roku. Are there different connections I can use for an og TV, that will offer a better picture on the TV, and that won't overlap? I have RCA connections on the RF modulator, but no RCA connections on my computer. I only have the S-video and the standard monitor connection.