Help... My PC is Steam driven

[Count Zero]

Every time I switch on my PC, I am prompted to login to Steam. I do not want this to happen, I only want Steam when I play HL2. I have tried to figure out why this is happening. I have looked in Startup and services and Steam settings, with no luck.
Can anyone tell me how to stop Steam prompting me to login to my account every time that I turn on my PC?

 

[GonzoBabbleshit]

It's in the Steam options menu

 

[diluted]

Settings -> Interface

 

[Count Zero]

Thanks guys.