1. Install Spybot Search and Destroy including tea timer (Tea timer monitiors critical portions of your registry for changes, including startup options).
2. Using spybot or msconfig remove the quicktime startup option.
3. Everytime QT tries to install itself tea timer will notify you and give you the option to deny it. You can even set the program to remember this change so it won't ever bother you again.

microsoft anti spy does all of that...shut the fuck up and get it

Not everybody has XP and can download that, for cripes sake... geez... dont be such a prick.

As an aside, you can also disable the Quicktime think in the tray by right-clicking on it, going to Quicktime Preferences, and selecting 'Browser Plugin' from the drop-down menu. There you should find a checkbox for disabling the tray icon... and yes, the heathens hid it somewhere where most would *never* look for it. :-)

I have Win2k.

I set up a computer with Win98 for classic gaming purposes and it worked there too.

First: You're a tool.
Second: Anti-spy is betaware and another poorly designed MS product designed to increase their hold on the consumer. I like a lot of MS products but this is a inferior product.
Third: You're a tool.
Fourth: Lighten up. I'm offering some suggestions based on what works for me (an IT profesional). If you don't like, don't use it.
Fifth: You're a tool.
Lastly: You're a tool.