I got my lollipop update yesterday. I was using it fine but it keeps restarting by itself several times. I have checked the power button and there is no issue with it either. Does anyone have this kind of issue?
Try a Cache Partition wipe. I can just imagine it not working but you might as well give it a go. I did one after the update...some say it's good practice to do that.
If you're sure of your backups, you could also try a Factory Reset. The consensus seems to be that we should do that after a full letter upgrade like this.