Software Not Installed Error with Free AVG 2011

My system is installed with Free AVG 2011, and I always get an error message "Software Not Installed". I keep on getting the error message on my Windows 7 every time I turn on the computer. This error message should definitely be related to the antivirus software and thus the AVG 2011 that I use. I am looking for the best cure for the error problem to this computer but personally, I don’t have good understanding of this operation. There could be a solution to my problem out there. Can get a possible solution that can get me out of this problem?
