Trying AVG ZEN free on Computer with Windows XP - Major Problems

I have an older computer that is very handy for me, however, felt I should update the protection that had run out some time ago. My son talked me into trying AVG. When I downloaded the free version the other day, everything went well, all the processes completed without any trouble. Then my computer had to restart and that's where the problems started. Would only start in Windows safe mode but was unable to do anything, everything I tried had some type of error - AVG itself had error "installation of product defective". After many problems decided to restore my computer however, when I did that the computer automatically restored to what appears to be default factory settings. I was not able to restore to a date of my choosing. Now it seems I have nothing. The icons are there but nothing happens when you click on them. I am very disappointed and frustrated and don't know what to do. I cannot even go on the internet to give access to technical support to see what they can do as IE will only access the url but cannot do anything further as it aborts the site and won't open it. What can be done? Right now very disappointed in the product..