Originally Posted by Zeria
Powering off and on isn't technically a soft reset though. Soft resets require pulling the battery for about 30 seconds.
But kidding aside: The power button will reboot the device, if you hold it until you see the option to power off. If you just turn the screen off, then nothing gets rebooted.
Only if the power button does not bring up the pop menu, will you have to pull the battery. Otherwise, it not necessary.
Here's what HTC has to say about the soft reset:
How do I soft reset my device? What is a soft reset? close
A soft reset is similar to rebooting a computer. You will not lose any data unless you have unsaved work open. To perform a soft reset, simply power the device off and then back on.