In reply to harold walmsley:
> ... The question is which would be best ...
I know nothing about the Talk Talk s/w, and I can't say which of the alternatives you're considering would be 'best' for you. Functionally, of course, all of these things do similar jobs.
My *advice* is to use Microsoft Security Essentials now that - finally! - Microsoft has addressed this general issue, and started to provide such s/w as part of its general Windows provision. (Had it done so earlier in the piece, the overall lay of the land would be different of course. I assume it's late to the party for commercial reasons, among others.)
Anti-virus s/w hooks deeply into the guts of the Windows, and can be the cause of mysterious bugs in the running system. We can *probably* trust Microsoft to introduce fewer such bugs than do other vendors of anti-virus s/w: after all, they have complete access to all details of the OS.
Whichever s/w you decide on, if you do decide to change the s/w, make sure you completely remove all traces of the 'old' s/w before installing the 'new': not doing so is another well-known way to introduce bugs and problems to your system.
Does that help? Good luck, in any case.