Hello, ojoflor.
Thank you for using Apple Support Communities.
From your post, we understand you're having some troubles with several apps on your MacBook Air. We'd be glad to help out. First, use Activity Monitor to try and see if there is anything using up your memory: View memory usage in Activity Monitor on Mac Seeing this error may be the reason other issues are occurring.
You can also see if the same issues occur in safe mode and with another user account:
How to use safe mode on your Mac
Set up users, guests and groups on Mac
Keep us updated.
Cheers!