Tv used to have Roku but was taken off and put on another tv. Now tv without Roku has no picture and no sound. Tv is hooked up to air antenna. Remote and buttons on tv do not work so cannot change source, can't do anything with tv. Tv does show light in front bottom and a red light on tv power button keeps blinking. Tv is a 2007 Samsung 19" model HDMT TV LCD LN-T1954H.
Your problem has nothing to do with Roku. There's a 21 page thread on the Samsung site about a flashing light and it doesn't look good. The only suggestion is to unplug your TV for 10 minutes or more and hope it works when you plug it back in. If it doesn't, service is probably your only option.
I couldn't find control info on your tv model, but I did find the LN-T1953. You can view a manual for it here: https://www.manualslib.com/manual/1146461/Samsung-Ln-T1953h.html?page=5#manual
If yours is configured the same, there are control buttons on the right edge you can use without a remote to change inputs, control power, etc.