I have, or I should say had a Garmin 500. I'd had it a year or so and following a software upgrade on Connect, the screen stopped working, still beeped etc, so obviously the screen. Googled it, and found plenty of users with the same problem, loads of solutions offered, but nothing worked. Couldn't remember who I bought it off so contacted Garmin who said it was out of warranty and would cost £65 to repair. Anyway, didn't take up their offer, got an 800...dont ask why, always fancied one. A few weeks ago came across the old 500 in a drawer, messed about with it and to no amazement it came on, somewhat garbled with symbols and letters flashing all over, put it on charge and tried it again later, the screen was still garbled but much better, then it just died again, still beeped, so obviously still a screen problem. Tried it again the next day and it's worked perfectly ever since. Weird or what?
Gave it to the daughters boyfriend who was looking for a comp. He's over the moon with it.