Hi dave
The old Linux machine (it's a REALLY OLD machine which was destined for a Single journey to the tip anyway - 512 MB RAM Pentium 2 machine) runs suse 10.1 really well (wouldn't dare trying any newer stuff on it). LCD switch is fine when I need an 'X' console. (For those who don't know Linux the 'X' server is the Video server from which you can select a GUI to run -- unlike Windows there is a lot of choice - the most popular being KDE, GNOME and XFCE -- for more info any Linux forum will more than help you - a good one is
LinuxQuestions.org). However I'm not advocating a switch to Linux by any means - but just explaining why I can dedicate a machine to online Banking.
If you have an old computer lying around (and a surprising number of people still do - you can still make good use of them in these type of scenarios - even if the hardware is incredibly old - a small home server is an example -- CPU doesn't have to be lightning fast for a home server.
Linux is really great on older machines (but that's another issue). I do a lot of free lance work and have to keep accounts etc for various Tax jurisdictions such as Iceland, Holland, Belgium, France, Germany (and worst of all the UK--they are a REAL Pain if you are not a UK National) . So Online banking / accounts is quite useful. Also by logging on to a dedicated machine then I KNOW I have to do the basic Boring but necessary bookeeping. There's too many other distractions on W7 machines .
It would be interesting to see how many people have had "Spyware / Malware/adware/trojans/infections on their computers even WITH av software installed -- might make surprising reading.
But whether you do or don't what I would always regard as mandatory is to have a CLEAN image of the Official OS ( Retail or OEM but from the official install discs) after it's freshly installed archived away somewhere preferably on a DVD (or two) -- if you have the Blu Ray DVD's you can comfortably fit as much as 25GB on a BD-RW disk which with typical backup compression amounts to over 60 GB of data.
This way even if you "Hard format" a disc to cleanse it -- you should do a full format and then write Binary zeros in EVERY sector to totally flush out any possible contamination and then re-install your Fresh clean OS from your image backup. I prefer that method than installing an OS from a Disc say obtained from a Torrent -- whilst latest builds are probably genuine there's always a chance that something could be in them which "Phones Home" as soon as you are online.
AV software wouldn't protect against this sort of stuff as the OS presumably has to be installed BEFORE you can add applications to it so the virus / malware would have been decently embedded and hidden by then (or the "Rootkit" already enabled). So in these scenarios it's too late anyway.
These days most Virus writers aren't just disaffected teens "knocking up malicious code just for the fun of it" but can be very sophisticated competant intelligent programmers who are doing this stuff commercially for organisations of various kinds you don't really want to know about .
One of the biggest "growth industries" is "Identity Theft". It's not too dificult to take reasonable precautions against this happening to you - but installing AV software on your machine and then thinking you'll be OK whatever you do is a total 100% sense of false security and in my actual experience you are more likely to come to grief than if you just take care and install none.
Care in computer use is still probably of far more use than any AV software - but there's NO chance of stopping young teens (and others) from downloading all sorts of stuff especially from those social networking sites.
Cheers
jimbo