I have been using Avast pro for a few weeks now and have not had any trouble. I did an update and now i cant get avast to open. It says that its on according to my Action Center, but there is no icon and when i click on the desktop to open it, that does not work either. I have removed the whole program and reinstalled it again and when i restart i get nothing. I’m really starting to get frustrated with this. I’m using windows 7 64bit.
Try rebooting twice. If that doesn’t help then you could try a ‘Repair’ by going to Control Panel/Programs and Features then choose Avast> click Uninstall/Change and scroll down to choose ‘Repair’.
Hope that helps. 
well the restart didnt work. So i did the repair. After it was done my Action center said Avast was out of date and to click to update it. I clicked and nothing. I clicked again and Nothing, and nothing and nothing lol. Then i restart and Nothing
Well i Fixed it. I had to run the cleaner in safe mode after i went to uninstall/change programs. When it booted in safe mode i had to chose a path. but i couldnt find anything in program files, but there was an avast folder in C:Program Data folder. so i uninstalled that. then restarted. Went and re downloaded the avast pro and Cha Ching good to go.