My avast 5 will not restart…am using vista…am new at this…need help badly…email me if necessary please
I recommand to not share your email (hide it in your profile) its not a go to do ! 
Did you do a clean install of avast 5 or an upgrade?
Did you have another antivirus on your machine prior to putting avast on your PC?
Do you have a firewall and/or other resident software?
Was your system clean PRIOR to installing avast?
When you say that avast will not start, what exactly is happening? Is there an orange ball in the bottom toolbar? Is there a red “X” through the orange bar? Is there a yellow triangle through the orange bar? Are you getting any other warning signs? Are any shields disabled? Does your system say “Secured” or “Fix”?
The more information we have, the better we can help you.
In the meantime, download free Malwarebytes’ Anti-malware (MBAM) http://www.malwarebytes.org/ for on-demand protection. This is compatible with avast as well. Run a Full scan with MBAM to make sure your system is clean if you didn’t have avast on your PC prior to this post and there may be a possibility that you have malware causing a problem.
Please post back with your answers to the above to we can assist you. Thank you.