Go to Start, then click on Run and type: MSCONFIG
Now click ok or press enter.
Now click on STARTUP (on the top on the right). Now you will see ticks, what you have to do is remove those ticks and it will prevent the program from starting.
To remove the tick just click the tick.
If you click here and scroll down a little and enter into the easrch the program name under "Startup Item" you can then see what program it relates to and weather it is safe to remove the tick.
For example Yahoo messenger has the startup name "Ypager" which is safe to untick.
When you have finished click ok and restart your computer and the programs will no longer load.