For the smashbros site, I can see the page, but no pictures load and it goes incredibly slow, and for vanguard, certian pages refuse to load.
This rules out your hosts file as the problem in fact I believe it rules out your computer as the problem.
I've been having a problem for a while in which I cannot access certian websites on my pc that I can access on other pcs with no problems.
It has to be something between your computer and your network.
I have no experience with home networks but I guess your computer has a network card and a cable that runs to a router or something.
Check the card, check each end of the cable connections, try another port in the router, move your computer to the location of a working computer.
I doubt reformatting will solve this, soldier on.
Edit: It will do no harm to try the following but I have my doubts it will help, go ahead and do it anyway so we don't have to ask about it later.
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Security tab
6. Reset all 4 security zones to Default
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Privacy
6. Restore 1 Default button
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. Advanced
6. Restore 1 Default button
You may need to do the following as well
1. Start
2. Settings
3. Control Panel
4. Internet Options
5. General tab
6. Remove cookies, temporary files and history
Kudos to Raptor.