Are you talking about the file (c:\windows\system32\drivers\etc\hosts)? You have to unchecked (hide protected operating system files) in folder and search options. I can confirm that spybot is not the problem. I also have spybot and can access the host file.
If there is an issue with re-direction, just editing the hosts file may not fix things as whatever is on the system will just re-enable things. Did you clean it out? I find that Malwarebytes does the best job of things.