error 0xc150004

Hello , I downloaded Avast free version and installed it , when it begins to start it shows an error 0xc150004 saying it can’t start , can someone help please ?

What operating system ??? What other Security programs installed ??? How did you remove your last AV program and what was it ???
How to Successfully Install Avast: http://goo.gl/VLXde

my operating system is 8.1 , I have malwarebytes installed , I had AVG and I uninstalled it from control panel

Follow the instruction in the link I posted. You need to totally remove AVG before you can install Avast.
Why did you remove AVG ??? AVG is owned by Avast and gives you just about the same protection.
The main difference between the 2 products is the User Interface.

Regarding Avast & Malwarebytes, see: https://forums.malwarebytes.com/topic/200324-exclusions-for-avast-users/