I have no experience with HostsMan whatsoever, but did you try to load a previous system restore point already?
That could be an easy fix.
I'm not sure if I'm allowed to do this, but the HostsMan support forum itself can be found > HERE <
If your HOSTS file itself is "corrupted", you could visit http://winhelp2002.mvps.org/hosts.htm
and get yourself a new one (including good instructions and a good explanation of what a HOSTS file exactly does) from there.
Furthermore, -usually- you don't need the Windows DNS service activated in the first place!
In fact, especially in Win XP and earlier, this might hamper your network-connections when using a (large) HOSTS file.
System specs? OS? Network Connection?
What I can see from the HostsMan site, it *shouldn't* have influenced any drivers or services, only the HOSTS file...