Liftmaster Remote won't close door

Liftmaster remote will not close door. No reverse problems, just not responsive. Remote light does come on when pressed, but does NOT affect the opener. No blinking lights or anything when pressed to close. 

It will open the door just fine. Remote Batteries are good. Checked sensors and all lights are green. Unit has been up since '98. (stop laughing). Has been reliable for many years. Wall control works fine. Should I just replace the remote? Why would it open, but not close?

Should I replace the sensors? If so, can I find some that would be compatible? Is there some rock I haven't turned over?

Have you put CFL fluorescent light bulbs in the opener instead of the incandescent bulbs? The low energy CFL bulbs (or even fluorescent tube lights in the garage) can cause interference with the radio receiver. The lights would be off normally when you open the door so it wouldn't interfere with the remote but the lights would come on when the door opens causing the interference.

If the safety sensors were misaligned or bad then it would affect the wall station and the remote. If you have to hold your finger on the wall station button to close the door then the sensors are misaligned or bad and need replaced. However if you can press & release the wall station button and the door closes then the problem isn't with the sensors.