It happens some times when you remove some particular program like yahoo messenger ,gtalk from system startup. But when you restart your system these programs get loaded again.
When you open msconfig will see a new entry for yahoo messenger in the startup tab.This happens because there is a option being checked in yahoo messenger which says automatically adds yahoo messenger to system startup when ever you run yahoo messenger.(as shown in the image below)
Removal of Yahoo messenger from startup , follow the steps given below
1. Open yahoo messenger and login to your account.
2. Click on messenger>>preferences click on the general category in preferences.
3. Uncheck the checkbox "Automatically Start Yahoo Messenger" and click apply and ok.
4. Restart windows
Startup removal Google Talk (Gtalk)
Almost same is the case with google talk ,as in gtalk there is another similar option which says Start up with windows
So, to remove gtalk to load at startup automatically with windows you will need to uncheck this option.
1. Open the gtalk click on settings
2. Uncheck go to the general category and uncheck the option "start up with windows" and click apply and ok.
3. Restart windows
If you have any problem in following the above steps lets us know through your comments.