Hi, I'm facing this problem that my computer is shutting down sometimes and dispaying a message mentioning "C:\WINDOWS\system32\drivers\etc\hosts" and something like: " settingsmodifier:win32/possiblehostsfile hijack". I have no idea what I shall do. Please any help?!

Have you done a anti-virus and anti-spyware scan?

You can download AVG (ree.grisoft.com/doc/28415/lng/us/tpl/v5)