My iMac 27" has been working great but within the last two weeks a couple things have been happening. When Browsing the web on Safari the screen would close and I would have to reopen safari (multiple times). Then as soon as it begins, it stops and the computer works fine. Don't really understand. Then, when I am typing, either in the url window or just typing in google (as an example), te keyboard makes strange beeping noises. It was doing all of this when I decided to register for this forum. Now that I am typing - everything works fine. any ideas what could be wrong?