Hi there I seem to remember pressing TT button and waiting for it to flash 3 times and NOT entering a code used to work.
Here is the latest I could find on TT site
Reset your remote
The steps to reset your remote will vary slightly depending on which remote version you have. 
Remote V1 and V2 (like the remote pictured on the near right).
Press and hold the 
and the YouView power button (top left) 
on your TalkTalk remote at the same time until the LED blinks twice then enter 977 using the number buttons. The remote is now reset and you should be able to use it.
Remote V3 (like the remote pictured on the far right)
Press and hold Digit 1 and Digit 6 on your TalkTalk remote at the same time for 3 seconds. During this time the red LED will remain off. After 3 seconds the red LED turns on, then enter 981 on the remote. After a valid key press sequence the remote LED will blink to confirm it's reset and you should be able to use it.