Further to Simon's security concerns I have spent the last couple of days investigating various flavours of Live Linux CD/USB Flash "Distros".
These are used often for Banking, Online Shopping and other activities that require total privacy and leave no trace of your internet activity. No Phishing, Malware, Tracking etc etc is possible. Did you know you cannot watch a Youtube video anonymously?
brianv's recommendations : SlackoPuppy Linux (250MB) and Tails Linux (1.2GB).
What to do?
Get a 2Gb USB Flash Stick first.
Now get
imageusb here:
http://www.osforensics.com/downloads/imageusb.zip( It does not install, just unzip it and run the exe. What it does is : It makes a Bootable USB Flash stick. )
Get your Linux Live Distro ISO : Tails
https://tails.boum.org/download/ [or] SlackoPuppy
http://slacko.eezy.xyz/download.php Insert USB Stick -> Run
imageusb. Select your USB Flash Drive and Select your Linux ISO from the Browse Box. CAUTION take care here!!!
Make sure you have only the USB Flash Drive selected! Triple check!! The procedure only takes a minute and when done switch your machine off!
With the USB Stick inserted, start your machine, hit F12 for boot options (yours may be different F2) and Select the USB Flash Stick. Depending on your machine specs you should have a fully functional OS in seconds...like mine

.
I'm posting from Tails Linux currently, my favourite as it happens. If
you decide on Tails read the docs about creating a persistent volume, and you will need another USB Stick. That's about it. Have fun!
Sorry, there's one more thing...You cannot
install Tails Linux on a Laptop or PC, if you want to do a full install, on an old [preferably later than Vista] Laptop for instance, you
will need SlackoPuppy Linux, and that's exactly what I did also.
Got any questions? I'll do my best!