Cannot activate Smart Security

I have used ESET on my previous computer without problems.
I activated a new account on the laptop 2 days ago without problem - it detected a trojan and appeared to delete it. The next day however the warning comes up that Smart Security is not activated on the computer. Won't allow me to reinstall or activate the virus protection. When I tried to reinstall the program gave me warning that I don't have authority to deactivate EKRN.

I have tried to uninstall and reinstall Smart Security but says I cannot uninstall program as it is not installed.

Have searched C drive for the ESET files and they all appear present - now in duplicate as I have installed it twice.

Any ideas how to get beyond this. I don't know if a virus of some sort is preventing installation but I had given the computer an indepth scan with Smart Security the day prior to all this happening so hopefully that cleared that.

Any help would be welcome.

 

try some basic troubleshooting
http://kb.eset.com/esetkb/index?page=content&id=SOLN2505