I just updated the systemsoftware and now can get past unlocking the screen. Every time I try to unlock the screen I get the "The application HTC Sense (process.com.htc.launcher)has stopped unexpectedly. Please try again" with a Force close button. It force closes whether or not I press the button. The loading window comes up for several seconds, then the process begins again and repeats again and again until the phone sleeps. I went through the usual steps - taking out the battery for 20 minutes, taking out the SD card etc - and the same thing happens. Any suggestions before I try a hard reset.
If you can't even unlock the phone before it force closes then there really is no option other than a factory reset. You can do this by holding down volume down and power until the recovery screen comes up...then use volume keys to arrow down to clear storage (factory reset) and press the power button...The screen says to press volume up for yes or volume down to cancel. If you hit volume up, the phone will reset, reboot and then you should be able to use the device again. You wont lose any media on the storage card since this wont clear the card.
Check out a fun infographic that teaches you how to increase storage, enhance security, improve battery life and clean your device.