How do I kill a process that cannot be killed in the usual way?

Have encountered the below issue 3 times already.

I launch a program - from Windows 7 startup panel
The program does not show up.
I try again and even a 3rd time.
Nothing happens.

Looking in the taskmanager first tab [Applications] the program is not listed there
Under processes it is indeed listed, but it cannot be killed. Period.
Trying over and over.

I then decide to close Windows 7 - if the program is listed I click on Forced termination (or something)
Windows then hangs at the blue logoff screen (Logging off..)
Nothing happens, 5 minutes, 10 minutes.

The only solution is use power button.

Q: how to kill processes that cannot be killed?

Note:the application is Windows 7 compatible.

Thanks!
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Thanks for your quick response.

It is PhotoStudio v6 (ArcSoft). Undoubtedly I can uninstall (and re-install) it.
Don't get offended, but eh .. I am unsure if that would solve the issue though.
Do you think it would help?

thanks again.
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