Qhosts is a trojan affecting all versions of the Microsoft Windows operating system.
On infected computers the trojan will modify settings in the hosts file. By modifying the hosts file, it can control where users are directed when they enter certain urls. For example, if the user types in paypal.com, they will be redirected to a different location and not the real Paypal site.
In this way, the trojan can steal login information and other private data. The trojan will also communicate with a remote server.
Any type of malware that alters the hosts file can be very dangerous. You may think you are typing in a legitimate URL, but instead you can be redirected to a remote location setup to mimic the site in question. Always check that you are on a secure site before entering private information (check the padlock in the browser). You can also check the hosts file.
c:\Windows\System32\Drivers\etc\hosts
