Question: Who invented CTRL+ALT+DEL...? 

Answer: Control-Alt-Delete (often abbreviated to Ctrl-Alt-Del) is a computer keyboard command on IBM PC compatible systems that can be used to reboot the computer.This keyboard combination was designed by David Bradley, a designer of the original IBM PC. Bradley originally designed Control-Alt-Escape to trigger a soft reboot, but he found it was too easy to bump the left side of the keyboard and reboot the computer accidentally. He switched the key combination to Control-Alt-Delete, a combination impossible to press with just one hand (this is not true of later keyboards, such as the 102-key PC/AT keyboard or the Maltron keyboard). More advanced operating systems use its status as a "reserved" combination for various purposes, but often retain the ability to trigger a soft reboot in certain configurations or circumstances. David Bradley is also known for his good-natured jab at Bill Gates, at that time the CEO of Microsoft, and also the creator of many of Microsoft's programs: "I may have invented Control-Alt-Delete, but Bill [Gates] made it famous", alluding to the perceived instability of Microsoft operating systems.
This question from the Yahoo Q&A forum is categorized in the topic: Education & Reference