Help both my CND uv lamps have stopped working

[Tina's Treats]

last week one of my lamps (both about 8 months old ) stated beeping after 1 second and turned off. I assumed it needed new bulbs so changed them ... No luck and reset button didn't work. On Friday exactly the same thing happened with the other lamp. I am obviously doing something wrong or not pressing the right buttons. Instructions don't cover this so has anyone had the same issue and solved it. Thank you

 

[x Fee x]

After changing the bulbs, did you press and hold the reset button until the LED display reset the timer to 100 (hours)?