If they are programs that you don't want loading then you'll need to disable them from running at startup. Remove any entries that you don't want from the startup folder in the 'all programs' list. Also type "msconfig" into the run box. Go to the last tab, Startup and remove ticks from any other programs that you don't want to start. You will be prompted to restart and when you next login you will have a box pop up, put a tick in the box and click OK.
If you merely want to hide the icons the right click on the taskbar and select properties. Tick the box that says hide inactive icons and then click the customise button. By selecting the icons you can choose whether to show or hide the icons.