Removing All OLD Anti-Virus

I could really use some assistance.  I have the privilege of working from home.  I log into my company through the VPN.  They made changes to it last week and now i can't get AVG to download (now required).  I always used AVG before I had to change to comply with the old VPN.  I have unnstalled and gone through the registry.  I don't get it.  But I need it to connect and if I can get the free version fixed I cna then go back to what I had before.  BTW- I tried that doing the free trial and got the same message.  I never in the past had issue whether any other was on it or not.  Do you have something I should try to clean the regstry?  Or am I missing something?
Sharon