I have just recently experienced a problem with my finder, iTunes and others applications on my mac, but I used the safe boot solution and it worked , the apps are now responding, but I have movies and music on my iTunes and I tried watching the videos on vlc but it's saying that my mac lacks quartz extreme acceleration who's is required for video output and my iTunes is not playing any of the songs and the volume is not working as well. Thanks
If you're indicating that you're in Safe Boot and your audio is not working on the built-in speakers of your Mac... that's expected. Safe Boot is a testing environment only and some things simply do not function there due to the imposed limitations of Safe Boot, for the purpose of testing.
If Safe Boot fixed your primary issue, then simply restart. If the issue is still resolved, then hooray. If not, then you have something causing an issue in at least one of the following locations: Launch Agents, Launch Daemons, Startup Items, or Login Items.