My Thomson digital tv recorder 500GB DT16021TUT is not taking commands from remote control after freezing when trying to set timed recording

First of all, check the remote control handset for its infrared emission. If found OK, try a reset to this set, and check further. Check the remote control for its infra-red emission. Check it with fresh batteries. Check by pressing all the buttons on it; and see whether all of it generates infrared signal while pressing. If it is found OK, check and replace the infrared sensor inside the TV. If you wish to get some details; check the site linked here. It has details about how to check a remote control; by one among the post. Surf the site with patience. Pull up older posts. http://electronicshelponline.blogspot.com/ If the remote control is found OK; check and replace the infra-red sensor inside the TV. Contact any service technician
There are two types of reset to TVs. The first is simple to do; a Hard Reset; and the other is somewhat skilled; is a Factory Reset (System Reset). To make it a hard reset, just unplug the TV from AC mains wall socket, and re-plug it back after 15 minutes or so. If you do this by overnight; will be better. If you want to make it a system reset [Factory Reset]; you have to enter its service mode option, and select the factory reset option. If you wish to get some details; check the site linked above.