I don't know how I did it, but I managed to break/disable my ctrl alt del function. How do I tell if its my keyboard thats broken or if its some software thats not functioning correctly?
open a word/text document and press a few random letters.
then hold ctrl + F if a find box pops up your ctrl button is fine
then hold alt + F if the file menu drops down your alt button is fine
finally try using the delete key to delete the text.