i have an imac, osx 10.5.8. suddenly the other day, i started to have "alex" voice on everything i clicked. I eventually got rid of that, but then developed robotic sounds on everything i click, and when i try to adjust the volume with the volume keys, they don't function for volume, but minimize my screen. i have a 7 yr. old who uses this computer, so i don't know what he may have done, but any help would be appreciated.