***Knock on wood*** my pc has been ok, but Facebook carries tons of problems. A lot of losers have nothing better to do than find ways to cause pc chaos in our lives.
There are links on there that have seemed super legit, posted by close friends & when I've clicked them my anti-virus immediately blocks this or that & warns me to never return to the site.
If it's happening frequently can you try an 'elimination diet'?
Stay off a site for a while then add another frequently used one & see if you can find the source that way?