How do i go in and choose what I want to be starting when my computer starts?

Assuming you are not running Win2K, you can use msconfig to remove startup programs that you do not want running at startup.
Go to the start\run box and type msconfig.
This brings up a utility that lets you set system configuration. Go to the startup tab and uncheck any programs that you do not want running at startup.

There are numerous free registry cleaner programs that also include startup managers.  Most of these allow you to simply remove a check mark from a box and the program won't startup.  The beauty of course is if you later decide you want that program to start you simply put a check mark back in the box.  There are also several startup managers that do the same thing.  Simply Google startup managers and select and test the ones you want

   The things fnlvn2 mentions (checking and unchecking items) can be done in msconfig.  Just go to Run and type, msconfig, and follow dlwolff0's instructions.

IF YOUR RUNNING WINDOWS XP,, THERE'S A FREE DOWNLOAD U CAN GET AT MICROSOFT,, CALLED "WINDOWS DEFENDER"  IT'S A GREAT PROGRAM,, , U CAN GO TO GOOGLE AND TYPE IN " FREE DOWNLOAD WINDOWS DEFENDER!!!  THATS WHAT I USE TO START AND STOP ALL MY START-UP PROGRAMS   GOOD LUCKKK TAMI