The lack of privacy is a major problem on the internet. People can, and do, manage to track and monitor what you're doing. Sometimes these people are advertisers and large companies, while other times they're hackers and criminals.
If you want the ultimate in online privacy, check out a system called Tails. The full name of the product is The Amnesic Incognito Live System, which gives some useful clues as to what it does. Amnesic because, after you've finished using it, it deletes all traces of itself and the memory it used. Incognito because it uses the Tor network to ensure that all of your web browsing activity is pretty much untraceable and anonymous. And Live System because, rather than an installable product, Tails is a complete bootable operating system which you run from a USB stick or DVD disk, perform whatever you need to do, then reboot back into your familiar (and less anonymous) Windows environment.
Tails is based on Linux and, as well as the anonymous web browser, includes a relatively full set of other features too. There's an office software suite, for example, if you need to create documents in complete privacy. Of course, you'll lose those documents when you exit Tails, but there's the option of creating an encrypted Persistent Disk area of a USB stick to which you can safely export them in encrypted form.
Tails really is the ultimate in online privacy, and has been used worldwide by some high-profile activists and campaigners. While it may be unnecessary for most people, it's a fascinating product, and a perfect gift for the paranoid. And because it runs independently of your existing operating system, it's very easy to download, play with, and then discard.
Tails is completely free to download and use.
Link to Tails Download