I have been using my device for about 2 years now and this has been a recent problem. Whenever my phone's battery dies or I manually turn it off, it takes hours(stuck at Motorola boot logo for 2-3 hours or sometimes more) for it to turn back on. It heats up quite a bit while charging, if that helps. I had my device rooted when I was using Gingerbread and used it mainly to take screenshots, but when I updated to ICS, I didn't unroot it and simply updated, this hasn't caused any major problem yet, other than a significant lag at times which I think is unrelated. Any help would be appreciated.