I moved this to a more approriate spot for support.
There are some hints and tools in this link: http://www.bleepingcomputer.com/forums/t/470562/snapdo-removal-from-google-chrom e/
(Disregard that the user there was asking about Chrome)
If those tools mentioned don't help I suggest starting a new thread there.
I would imagine that Malwarebyte Free would be sufficient as this malware has been around for a while but there may be new variants that elude antivirus/antimalware.. Hint: to keep Malwarebytes actually free, simply refuse the trial offer.
There are more tools and jhints in the last link in my signature below.
No, it's not a virus, and it's not a Trojan. What it is is a browser hijacker and home page replacement.
How to get rid of it depends on which browser you're using. There are lots of suggestions in the Google and Mozilla forums, and some of them at least seem to work. Check these threads for those suggestions (read through the posts, see what works).
This thing often comes as a bundled add-on when you download something from CNET (for example). You need to watch for those innocent little would-you-also-like insertions into the download pages.
After it's gone from the browser run either Malwarebytes or AdwCleaner to clean up the traces. If you use AdwCleaner run it first in Search mode and check the list of things it proposes to delete. It deleted SiteAdvisor when I tried it out :-)