No. I am not able to change the fuses in AVR studio now. The AVRISPmkII programmer needs a clock signal to operate. But, the clock of the micro controller is wrongly fused as external clock generator instead of external crystal oscillator.
I came across this site, http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&t=106325 . But, I don't know if the recovery procedure is for an integrated and assembled atmega2560 micro controller as an arduino mega2560 board.
Please suggest what can be done now to recover the fuses ?
Thanks.