The volume control can be disabled in the Control Panel usually. Look in the Sounds applet and uncheck the box that says display the control on the taskbar (which --is-- indeed the system tray as in # 1's answer).
Real player's default installation has it running in Startup. You can disable it as #1 says in the program. Lots of these downloadable softwares will do this and you just have to hunt around for the option box to uncheck. You don't want these programs loading until you start them--Real Player, AOL, Earthlink, etc. ISP's that are dial up shouldn't be set to start automatically.
Your network icon would be Novell, I'm guessing? If that is the case, leave it alone unless you're the system administrator. If you are on the network when you start up and log in, this needs to be there.
Your anti virus program should also be running when you have the PC on. Reasons are obvious. You may want to adjust the settings for automatic scans and loosen up how often and how deep the PC is scanned.
To find what else is running at start up, look in Windows Explorer. The path is:
C:\Windows\Start Menu\Programs\Startup
This is for Windows 9x systems. You did not say what OS you're running on the workstation.
Programs that could be in startup that can slow down the PC performance are:
MS Find Fast
MS Office
Office Shortcut Bar (this one I usually leave in)
You can safely delete the find fast and ms office as they're just shortcuts to the programs, and not the programs themselves. Also, sometimes find fast causes excessive grinding of A:\ drive.
Best wishes.