I recently updated my software on my computer, I believe it was the new os, airport, security and one more. But since it has been updated my computer has become extremely buggy. I have trouble restarting the computer, so I have to do a forced restart. Once it powers on I can open an application, after that the computer basically stops working except for that one application. So if I run Safari it will only stay on Safari and if i try and use another application it will not let me open it and this message comes up "You Can't open the application (null) because it may be damaged or incomplete." I also cannot switch back to finder, I can only stay in the current application I am running. I am currently running disk utility to try and fix the problem. It seems that the main problem that disk utility has found so far has been in the airport software. Has this happened to anyone before and does anyone have a suggestion as to how I can fix this. Thank you.