That part of the taskbar was called "system tray" in Windows 98 and ME. Windows XP calls it "notification area". Just so you know. No problem with me how you call it.
This aren't just icons, it are running programs showing an icon there so you can activate them if you want. Examples include the 'safely remove hardware' icon, the 'volume control', Nvidia control for your monitor settings, Zonealarm firewall, anti-virus program. And some mediaplayers (like Real Player) do it.
There are two possibilities to get rid of these icons:
1. If you need the program running, but don't want to see the icons, those programs sometimes have a setting that lets you choose to show it or suppress it. That really depends on the program. Sometimes they haven't (like the 'safely remove hardware').
2. If you don't need the program running, it's nearly always possible to do so. Maybe the program has a 'run at boot' option that you can uncheck. Or you need to go to the startup tab of MSCONFIG (start>run>MSCONFIG) and uncheck it in the list.
If you tell what icons you have (just click them, or right click them to see what the are, or point your mouse at it and see if the have a yellow tool-tip) we can tell you for each of them what to do with them.
So waiting for your reply.
I found the right bottom tray had more items added and its length grew.
May I know how to delete some icons in the bottom tray?