I suggest you to install and use ESET Smart Security, because it is lighter to PC performance than Kaspersky Interent Security. You can find out about this Anti-virus on Download Internet Security :: All-in-one Smart Security :: ESET. And not to forget, there is a program that automatically searches licenses on Internet and enters them in this Anti-virus software. The program is called "TNod User and Password Finder".

If you want to see witch version is your Windows version, just select Start->Run and type winver. This will tell you wich version is your Windows Operating System