OBASHER, this is not a fix for your issue, but on a remote that old, if you still have the remote opened up, take a Q-Tip and some contact cleaner or alcohol and clean the contacts on the backside of the rubber button pad and the circuit board where the buttons make contact. You'll be surprised at how much dirt builds up on the contacts over the years. Then if you do get it working again properly you will notice a big difference in the responses to your commands. No more having to push buttons twice cause nothing happened the first time.
Now as far as your issue is concerned, this has also happened to me. It ended up being the CONTRAST somehow gets turned all the way down to nothing. Try this. With the tiu turned on, try pushing the power button on your remote like you would when you normally turn it on. Wait about 10 seconds to give it time to exit the introduction screen. If you don't have the tiu powered up it will stay on the introduction screen longer. Now press the menu button once. Roll the thumb wheel down 2 clicks and press the thumb wheel in once. Roll the thumb wheel down 6 clicks and press it once. Now roll the thumb wheel slowly and continually upwards, without pressing down on it, several times until you see the screen coming back to life. You may have to roll more then 10 times. If it didn't work, pull a battery and put it back in so that you know the remote powered down, then try again.