Yes, we are all more used to that on Windows, but occasionally Linux seems to not respond. It's usually still alive under there, here are some ways to regain control without resorting to the power switch.

1. SSH in to it from another computer. This is great, if you have another computer, a network and the SSH server is running. If you can log in, su to root and issue halt or reboot remotely. Or you could try to fix what's wrong.

2. Log in again on a virtual terminal/console: Ctl-Alt-F1 (or F1 through F6)
Log in as root, fix things or restart as needed. You can get back to the GUI with Alt-F7

3. Nothing works, it seems to be dead. It's probably not really dead. As a last resort, try the Raising Skinny Elephants Is Utterly Boring. Alt-Sysreq (Sysreq is often also the Print Screen on some keyboards) with each of those letters. Alt-Sysreq R (wait a few seconds) Alt-Sysreq S (this one is Sync, you might give it a minute or two) and so on with the first letter of the phrase. More info here:

http://en.wikipedia.org/wiki/Magic_SysRq_key

I have not ever had to do this with 64Studio, but it is good general Linux sysadmin knowledge.