Romeo29 has beat me to the punch,
so please forgive the duplicate info. However, there is some additional info, so I'm posting anyway.
Let's try using the Avast uninstalling utility. Go to the following webpage and follow the instructions there--the instructions are pretty clear but if you have any questions don't hesitate to ask:http://www.avast.com./eng/avast-uninstall-utility.html
If you are not sure how to get into safe mode there is a tutorial here:http://www.bleepingcomputer.com/forums/ind...showtutorial=61
Let us know how it goes. And I have to ask because your answer is very important--why does your husband want to get rid of Avast? Have you tried to replace it with another Anti-virus? If so which one? It is not safe to be on the internet without an antivirus installed. Before you remove Avast, you should take your computer off-line--unplug the cable if you are on high speed or just disconnect if you're on dialup.
If you have installed another antivirus, you may need to uninstall both to get one working correctly when it is reinstalled. Never install more than one antivirus that includes an On Access/Real Time scanner at one time. If you do need another antivius, download the following, as it is very simple to use, and once Avast is gone, install it before going back online:http://www.free-av.com/en/trialpay_downloa..._antivirus.html