Hello, B_G, this message is caused by a pgm trying to access incorrect memory addresses, a pretty obvious thing in your case where it tries for 0x00000000. Bad programming is often found in malware, so may I assume that you have been infected by something which cannot even run properly? Unless its aim is just to break explorer [taskbar is part of explorer].
But explorer is just the GUI, and you can work without it.
Is Task manager working? [ctrl-alt-del, usually...]. If so, go to TM, File, New Task, and paste or type in:
http://download.bleepingcomputer.com/sUBs/ComboFix.exe
==Download that file to your desktop.
- to run it dclick combofix.exe and follow the prompts to start it. When finished, it will produce a log, C:\Combofix.txt - post that log in your next reply.
A word of caution - do not touch your mouse/keyboard until the scan has completed. The scan will temporarily disable your desktop, and if interrupted may leave your desktop disabled. If this occurs reboot to restore the desktop.
If that log file does not open, or you lose it, just type C:\Combofix.txt into that same Run window in TM.
Next: Run this:
http://www.majorgeeks.com/download5554.html
-copy that download to a new FOLDER placed either alongside your program files or on your desktop and then... rename hijackthis.exe to imabunny.exe
-in that folder start HijackThis by dclicking the .exe; now close ALL other applications and any open windows including the explorer window containing HijackThis.
-click the Scan and Save a Logfile button. Post the log here.
## You may find it easier to copy those logs to a removable medium and post from your other computer. Or you can try it all from Safe Mode with Networking. Your choice.
Unsolved 
