My LG LCD TV has HDMI slot but DTH receiver has component connections to TV and USB port but no HDMI so how could I have HDMI connection from DTH receiver to LCD TV please advise.

Does the box have a DVI connection? If so, and the TV has an HDMI input paired with audio in, then you could use a DVI-to-HDMI cable paired with an analog audio cable (the red and white).

The paired audio is required because DVI does not carry audio.

If not, then you will need a new receiver. You can still get HD through component. If you are not satisfied with the picture quality, but do not want to get a new receiver, you could try upgrading to higher end component cables.