"Slide to Unlock" intermittently unresponsive

I don't have the original but how often do you reboot. I've only had this happen once. I held down the home button until I got a quick black screen and then the home screen. Seemed to work for me.

I have the same EXACT issue with my 1st gen. iPhone. I notice that when the sim is out and I wake it up out of it's sleep, the "no sim installed" button shows up and the screen does NOT respond to my touch to close the button. I think this problem has to do with when the iPhone wakes up. It affects the whole screen, not just the "slide to unlock". It also happens when I get a phone call when the iPhone is sleeping, the "slide to answer" doesn't respond to my touch. It's more annoying than anything, but should get fixed. I hope that Apple fixes this bug IMMEDIATELY!!!

I have had this exact same issues as well. Also a 1st Gen phone. Completely up to date. I notice that it ALWAYS happens in the morning, when I first go to use the phone. Sometimes the battery dies during the night, sometimes not. When it is alive in the morning, and I try to swipe to open, it does not respond. Like the OP, I have had varying success with different combinations of the mute, home, sleep and combo's of said buttons, while activating the screen. I have also had success, using the sleep button to turn it on, and holding my thumb in the area of the slider as the screen turns on.

I will note that I have only started experiencing this problem with the newest firmwares, 2.0, 2.1, 2.2. Before that, I never had any sort of issue in the past. I also have one small dead pixel in the status bar of the springboard, but as it's nowhere near anything that I have to "click" on, it's not a problem for me.

Like the other poster's, I am hoping that this issue gets fixed pronto, since it's causing me to miss calls, since I can't slide to answer....

You're not alone. The same same thing happen to my phone. It started out gradually and now the bottom half of the phone don't work. This only started happening since i update the software. I took it to the store and all they said to me was to get the new iphone 3G. They don't have no intention of servicing 1st Gen

I suspect it may have something to do with the new update too. I have the volume slider and the brightness slider exhibit those problems. I find that I can get them to move if I press real hard. This is a projected capacitive touch screen rather than a resistive type but it appears that flattening out your finger to take in more area seems to make things happen. It seems to be more prone to happen when the iPhone is burdened with activities. Give it a try and see if it works to press harder and hope for a software update.

I have the iPhone 3G, and "slide to answer" is suddenly not working reliably (after 4 months). When answering calls recently I have had to try sliding it 5 or 6 times before it responded. I have no problems with "slide to unlock" which (currently) seems to work every time. So this is not just a first generation problem.