I've always cleared all items found in:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run

including systray.exe

When my computer boot, if I Ctrl - Alt - Delete

the only Program running is Explorer.

I have done this for years and never had a problem.

So why do people say you have to leave systray.exe

What does it actually do?

displays the sound icon, and the usb icon thats about it

Why does the Java icon still load next to the time then?

it probably doesnt use systray for the icon because you can still see icons down there without systray.exe, systray.exe only displays the windows related stuff

So its not really needed?

I'm on your side. It's not needed, even to display the tray.

But it doesn't take that much resources though...

i agree its not needed really, its just be say its needed, people say you should always have at least explorer and systray running