boot scan shows cyclic redundancy error in this file:
c:\Program Files\AVAST Software\Avast\setup\part-prg_ais-8b1.vpx
What does it mean and what do I need to do to fix it
are you able to run avast repair?
controlpanel > ad/remove programs > avast > uninstall/change > repair
The add/remove programs may be listed as Programs and Features on your system. 
Sounds like a hardware problem with the hard disk.