how do i change the setup so im not automatically signed in when i turn the cpu on?

Answer 1

Two ways to logon - fast user switching or use welcome screen. Looks like you want to have to logon with an ID and password.

Use the classic logon screen
To temporarily use the classic logon screen, press CTRL+ALT+DEL two times on the Welcome logon screen.

To configure Windows XP to use the classic logon and shutdown screens for every logon session, follow these steps:
1. Click Start, and then click Control Panel.
2. Double-click User Accounts.
3. Click Change the way users log on or off.
4. Clear the Use the Welcome screen check box.
Note If you turn off the Welcome logon screen, you also turn off the Fast User Switching option.

Answer 2

setup an administartor account by clicking the start button > control panel > user accounts

you would already know this if you had read your computer's help pages.