To safely access the dark web, always use Torbrowser from torproject.org
Ideally instead of using windows, you can use Tails Live CD as your more anonymous operating system.
Always make sure to encrypt your hard drive with tools like truecrypt.
When you buy something on the dark web, always tumble or mix your bitcoins before you spend them on some marketplace.
There are many good bitcoin mixers listed on the main page on darkweblinks.wiki
So go and check that out if you plan on purchasing anything illegal on the dark web.
It is always better to use as much protection as possible when it comes to securely using tor hidden service websites.
There have been many people busted by law enforcement recently.
So always tumble your bitcoins and stay safe!