Best 5 reason for PC hanging agian and agian

There are many type of problem by which reason pc is agian and again hanging

1. sometimes we are not use antivirus and not upto date antivirus by which reason many type 
                 viruses  attack the system  and then delete important files from the system man   diagnostic certainly cause the system not working properly.

2. sometimes it happens you are using which antivirus in which firewall is disabled
                  by which reason your after restart your pc hanging ..so always keep on remebring your          
                  antivirus  firewall should be enabled.
  

3.  Overheating Processor

       sometime it happens that our pc inside all fans are not working prperly
       as a processor fans, and grafics is not working by which processor is heating
       then pc is hanging.

4. RAM (Random Access Memory)  is bad or dirty may cause the computer to stop working all of
                                a sudden even the blue screen or restart.

      
  5. hard disk   - in hard disk comes bad sector torjon malware viruses attacting. it may big reason
                            for hanging.