Screwed up Windows GUI.

Sometimes when I start my system, the User Interface s really messed up. File icons missing on desktop and windows explorer, controlbox buttons missing, buttons don't have borders, application icon missing in taskbar and system tray etc. etc.

Though this happens only once in a while (maybe 2 or 3 times a month) and restarting the PC corrects the problem.
System configuration: Windows XP SP3 running on 3.4 GHz Dual Core CPU and 4 GB RAM

I'm trying to figure out the cause of this problem.

Have a look at the attached screenshots.

I am not sure of the reason but you can do this to save your self a reboot :D

Press ctrl-alt-del.
Click on Task Manager.
Click on the "Processes" tab
Click on "File" in the Task Manager menu.
Select "New Task (Run...)" and type "explorer.exe" (without the quotes) in the "open" field.
Click 'OK'
You will see everything is back to normal ;)

Maybe some system file is damaged. Get a hold of a WinXP install CD and try "sfc /scannow" (http://www.updatexp.com/scannow-sfc.html)

Have you tried updating the graphics driver?