Try booting into the Safe Mode to see if you have the same problems. Shut down the computer and then power it back up. Immediately after hearing the startup chime, hold down the shift key and continue to hold it until the gray Apple icon and a progress bar appear. The boot up is significantly slower than normal. This will reset some caches, forces a directory check, and disables all startup and login items, among other things. If the system operates normally, there may be 3rd party applications which are causing a problem. Try deleting/disabling the third party applications after a restart by using the application uninstaller. For each disable/delete, you will need to restart if you don't do them all at once.
If that doesn't work either, restart normally, then go to Applications/Utilities/Console. Note the exact time you are trying to open an application, then post the Console log at the time. Please copy and paste the log (not a screen shot) and limit the post to that time. Do not post the entire log please.