tv tuner

Sorry for the newbie question. I have a receiver provided by a local vendor here, and i choose channels from the receiver using remote control, can i redirect the whole streaming into a TV tuner card and switch between channels from the computer? or it must be streaming just one channel...

I bought a new iball tv tuner, which has vga port , But when i checked my All in one Dell desktop it doesn't have VGA port. Please suggest me wt to do? 1. VGA to HDMI converter will work or not , because desktop has HDMI port and tuner has VGA