You could also go to
AVG Anti-Virus and Internet Security - Real-time protection against viruses, spyware and malicious websites and type AVG Free in the search box.
Support for version 7.5 is coming to an end on 31st May so as was suggested earlier go for version 8.
Be careful as there is a paid for version 8 as well as the free version 8. Just make sure that you select the right one.
Llewiitha