First, go back and rename the HOSTS files back to their original names.. IN regards to the HOSTS file that you're going to end up using, REMEMBER, it must be named HOSTS with NO FILE EXTENSION in order for it to work.. (You'll need to have all file extensions showing and it can't have a file extension such as .txt at the end.)
I use an extremely large HOSTS file by HpGuru (now HpHOSTS) and I edit it substantially each time I replace it with an updated version.. IN order to edit the HOSTS file, double click on the true HOSTS file which should reside in the C\Windows\System32\Drivers\etc folder.. If it's the correct HOSTS file, an "Open With" window should load which asks you to "choose the program you want to use to open this file".. Scroll through the programs and double click on "Notepad".. When Notepad opens, you should see a HUGE list of websites that belong to the "banned" list.. In order to edit the list, click on "Edit" in the upper left, choose "Find Next", then type in the name of the website you want to allow.. (For example, typing in "myspace" might bring up a number of listings where those letters are used.) Find the EXACT website of your choice, highlight it, then press the "Delete" button and the website listing will disappear.. Pressing the "Backspace" button now will cause the extra space left by the deletion to be removed.. You can search for all listings with the "myspace" letters, or your website of choice, by repeatedly clicking on the "Find Next" button.
One other note about using a HOSTS file.. Make sure to disable the "DNS Client" service like this. (The DNS Client service will cause a huge slowdown in your computer when a large HOSTS file is used.) : Click on Start-Run, type: services.msc, then click on OK. When the "Services" windows loads, scroll down till you see the "DNS Client" listing and double click on it.. When that window opens, in the "Startup Type" line, use the drop down arrow to select "Manual", then click on the "Stop" button in the "Service Status" section.. When that's done, click on "Apply".
Hope this helps.