For those times when Windows completely freezes and you can't
even open the start menu, you can also restart your computer from
Task Manager instead of just powering the machine off.
Doing a hard reset isn't as healthy for your computer's
internal components, this method would be preferable if possible.
There are two ways you can bring up Task Manager:
Once you are in Task Manager, you can restart a hung process in
the processes list, or you can click on Shutdown \ Restart to
restart your computer.
Pretty simple, but very useful.