DNS hijacked? What symptoms or conditions lead you to that assumption? Do you mean your 'hostfile' instead of DNS ? Although that DNS spoof is possible, it's more of a WAN/Network issue, as opposed to a client issue.
Spoofed Certificates are becoming more prolific, and because browsers have 'trust on first use' behavior, it may be your SSL CA was spoofed for a single session or series of connections, and you were directed to a criminal website set up to mimic the genuine article.
Firefox, with these add-on's helps keep tighter controls on Certificates:
Force-TLS;
Certificate Patrol;
Perspectives;
and "NoScript" is the single best all-around malware and hijacking deterrent there is.
Find 'em here: https://addons.mozilla.org/en-US/firefox/collections/dunbar-pappy/dunbarpappy/
For hostfile defense, try this:
"HOSTS file" (from mvps.org) which blocks evil webpage assets from re-directs which install malware or trashware. (Vista requires special instructions; on-page link)
http://www.mvps.org/winhelp2002/hosts.htm