Hi there,
Please take a step back and tell us about your computer, make, model, CPU, RAM, OS using.
Also very important is when your computer worked normally last, and what have you downloaded or installed recently, that may have affected your icons.
Also be more specific as to what ICONS are present and absent. For example, do you mean your volume control is missing from the notification tray, or your WiFi or wired network icons are missing. Does the takbar look normal, just without icons, is the taskbar locked?
Finally, is this a work related computer/lapatop that could be affected by Group Policy or a home enthusiast computer?
That way the group can help you pin down the problem.
A simple example, some of the dell Win-XP computers have the speaker icon disappear which can be reset, and some of the WiFi adapters cause icon changes that can be corrected by making a change in the Windows Features area.