If this is when you boot up it looks like some startup file is attempting to load something that is no longer installed.
Have you uninstalled anything recently, or removed any viruses or other malware?
If so, have a look at MSCONFIG, (Start > Run, type in msconfig then click OK), then the Startup tab, and check down the list for anything that looks out of place. if you find anything, remove the tick, click Apply/OK, then reboot.
Every time i switch my system i get the following error "The exception unknown software exception (0xc0000024) occurred in the application at location 0x7c964ed1.Click on OK to terminate the program" and the title bar shows "setup.exe -Application Error"
Any idea how to fix this? I'm running windows xp
here's a ScreenShot http://img87.imageshack.us/img87/1244/20707096.jpg