Tech Support Scam?

When browsing yesterday, I got a web page (screen shot attached) that said "You were being hacked. We have stopped it for now. Contact Technical Support Now. System Health is Critical."

I assume this is a scam, but I am concerned about how someone could have actually gotten that onto my computer.

Note that the web address displayed is support.microsoft.com and the phone number actually appears as the phone number of a divorce attorney in Wichita, KS (the number is listed on their website, unless that is also a spoof).

I have never before used Norton Safe Search, but just renewed and upgraded to Norton Security with Backup and thought I would give it a try. The search that led to the scam site was literally one of the first few searches that I have done with Norton Safe Search. I am absolutely dumbfounded that Norton declared this scam site to be a "Safe" site (don't take my word for it; check out the attached screen shot). This leaves me wondering whether I can trust Norton Safe Search.