In the start>run box type MSCONFIG, press OK, and in that program go to the Startup tab.

For APCMAIN I found:
"What is the apcmain.exe location, where is it stored on my computer?
This will show in your startup program list as C:\Program Files\Ascentive\Performance Center\ApcMain.exe -m"

Does this ring a bell? If you intend this program to run and it gives an error, reinstall it. If you don't want it to run: uninstall it or at least uncheck this line.

Now reboot. If the other message didn't disappear, find out (by elimination) what startup program causes it.

Kees