Is there any way to totally stop a program from running, like to prevent the program from ever running?

Delete it.

Or quarantine it with an antivirus program.

Remove it from startup too with msconfig.

if you are trying to stop a program that is starting with wndows and runing in the background there is a good freeware tool called WinPatrol that will do this.

http://www.winpatrol.com/news.html

Why use programs, there is a easy way to get rid of startup programs.
The solution : msconfig.
Go to run, and msconfig, and then startup.

I have this really cool (free) program called Process Guard, or PG. It finds every process that trys to start up, and you can Allow, Allow Once, Block, Always Block.

Its great, when spyware/virus's/trojans download and attempt to run, it finds them and asks you what to do. You could just block your program in this case.

At first its annoying, because everytime you try to start a new program you havnt ran before with PG isntalled, it asks you, but after you say Allow (as in always) on all your apps, its great.

Not all Microsoft operating systems have msconfig.

uninstall it, or
remove it's shortcut from the startup folder, or
remove it's program entry from the
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
or
HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
registry key
Also programs like ad-aware and spybot search and destroy are good at removing unwanted programs.

I think he meant keep it running from general. Of course HiJack This and msconfig and alphnumeric's advice will keep it from the startup, but not forever.

I like the process guard suggestion, haven't tried it yet. Delete of course is a guarenteed way of killing it (unless it's viral or rolled back) Quarentien might work. Yeah, I know, nice spelling, so sue me.

ieSpell is a free Internet Explorer browser extension that spell checks text input boxes on a webpage. It should come in particularly handy for users who do a lot of web-based text entry (e.g. web mails, forums, blogs, diaries). IEspell

Hey, I wouldn't be a hick without my accent.

I found another thing that will keep a program from running.. it's called SirCam.

*sigh* I woulda hoped all my clients had patched their machines. I was wrong.

Add/Remove programmes in Control Panel. To completely remove any trace you will probably need to Edit the Registry but be careful, make a Registry Backup first.