Yea, it is a subscription service. You can use the one subscription on three computers. I use it here on xp and it seldom requires any attention. It just does its own things silently in the background. Every now and then you will see a bubble saying its up to date. Updates itself automatically and frequently.

Avast is a very good Anti virus program but nothing more. I use it on one confuser. For spy wares you should consider AdAware, Spybot Search & Destroy and Spywareblaster. These are not the only ones there are others as good but these three generally get all the good comments and are recommended often even on this site. Personally I run all 3 on all 3 of my machines. I look for updates once a week generally unless I see an update notice posted on another site I belong to. If I have been sensibly surfing then I will run them every 6 to 8 weeks. If I have wandered into doubtful sites (looking for free clipart, fonts or other freebies) then I will run them that night to rid myself of the phone home spies that will have inevitably appeared on my computer.

you may have malware now on your pc that is causing the McAfee problem that is the method many use to stop the antivirus on the pc from working, I would suggest trying to download, update and run malwarebytes to see if it finds malware. Some types of infections will also prevent you from going to security sites and getting the needed programs if you can not access security sites you will need to download the program on a clean machine to cd or flash drive then install it on the infected pc. Malwarebytes' Anti-Malware download, install, update, run full scan, allow to remove, reboot.

The attached link will take you to a recent PCmag.com competitive evaluation of AV products. PCmag (formerly PC Magazine) and in particular the author of this study are well known and have long-held reputations for being unbiased. Neil Rubenking's expertise has been recognized for 25 years or more. Flip through the article, you'll see they rate both free and for-sale systems. The Microsoft product gets consistently mediocre ratings in most comparison testing and evals. This author, as many others you'll find, suggests there are better choices. If you'd rather have a comprehensive security suite, here's another recent article Rubenking wrote. Note that the prices shown are probably MSRP, most of these can be purchased for substantially less money than what's shown. http://www.pcmag.com/article2/0,2817,2369749,00.asp Here is a link that might be useful: Anti virus ratings