I see that a lot has happened to the OS so nothing is assured. But given you have choices of free antivirus such as the one at Google, Free AVG, Panda Cloud, Avira why not try a few others?
I upgraded my Kas IS 2009 to IS 2011. I then upgraded my Vista Business to Win 7 Ultimate. Three attempts, as recommended by Kas tech support, to uninstall Kas IS 2011 by Kas Removal Tool and reinstall results in a pop-up box saying "the operating system has changed since Kas IS was installed. Please reinstall Kas IS". Two Kaspersky on-line chats with tech support were hopeless. The last one lasted 20 minutes with the only tech reply being "checking". As I still have a year left on my license, I am reluctant to pay for Norton or MacAfee. I have a one year old LG laptop that has nicely worked on Vista and Kaspersky 2009. Any advice on how to help this IT challenged Neanderthal?