well just one question, have you held the insert key so that you can change the speed of the cpu in the bios? needs to be set..
when you turn it on again, if just a black blank screen, just turn off for 30 secs max, then turn on, hold the insert key and wait for the beep.. if that works, just change the speed of the cpu in the bios and save it when you exit!
i have had this problem plently of times, it normally happens when i try overclocking it or if its not got enough juice going into it.. have you tried it with the 700 mhz duron in after you put the 1.1 in?
If it blows up? Opps.... I must have been doing something wrong