whay would happen if i wrote to non existant eeprom location?

Ahh, idk what but something screwed up mu mega overnight, i had ot on a nicad bateru overnight and the battery was dead when i got to it,(old battery probably dodnt hold a charge ) but its not being recognized anymore by my computer, so i tried uploading a new program wirh arduino as isp and usbasp, and both say its not responding
And with the program i had running theres no way to know if its doing anything, and after the arduino as isp attempt i dont even get the bootloader led flash
this particular mega had been burned up previously but some parts still worked for this project, well until now : /