Wow GK, 15 seems a lot! Although the number of icons by itself isn't important, it suggests that there may well be processes running that are using resources (CPU/RAM/IRQs) that are slowing down the PC.
Of my nine icons, I can get rid of two straight away by logging off the LAN and the Dial-Up I'm using to be here. Two more are for McAfee (using resources), one for the firewall (resources) and one for dial-up sharing (resources). There are a couple more status indicators (no resources) and the volume control. And that's it.
Have a look at your Task Manager by going: Ctrl/Alt/Del and then "T" or click on Task Manager. There you can see the programs running (Applications/processes - call them what you will). 25-35 is a normal range for my PCs. The higher figure is for the Dial-Up master. It's 34 as I write. Several processes don't have icons (eg TextBridge Instant Access). Under the tab for Performance, I'm using 1-2% of CPU and 123K Memory.
Your 15 icons suggest too many processes are running in the background consuming resources. As we said above, check out the Tools/Options/Preferences etc for some of the icon related programs to see whether you need them all the time. Although you have only four in your start-up folder, many more can be started by settings in the Registry.
(edit)Oh, I couldn't find system tray in my TechNet library either but there was something under the word "icon" that led me to the MS knowledge base articles.
[ 07 November 2001: Message edited by: fobotcso ]