I did this one to one of our sales staff, known not altogether affectionately as "The Weasel".

Edited his autoexec.bat file to call a batch file that was along the lines of:

cls
echo "Fatal Boot Error at Memory Location 14bf??:ffff"
echo " "
echo " "
echo "Press any key to Continue"
echo " "
pause
echo "Fatal Error at HDD Controller"
echo "Do Not Continue this Process or Irreparable Hard Drive Damage Will Occur"
echo " "
echo " "
echo "Call Packard Bell Technical Support for Assistance at 1-900-555-1234"
echo " "
pause

and of course the 1-900 number was a phone-sex line. It was staggeringly funny listening to the Weasel trying to explain a boot memory allocation error to a lady whose only idea about boots were thigh-high and leather and God only knows what she was thinking when the topic turned to his Hard Drive. Could have been worse, I guess -- the batch file didn't talk about his Floppy. :-)

tanstaafl.

"There Ain't No Such Thing As A Free Lunch"