Hillary Clinton is back on the attack ... blaming the Internet, at least in part, for her loss to Donald Trump -- and she's demanding some big changes.

HRC surfaced in D.C. for Sen. Harry Reid's going-away event, but when she got on the mic she went off about "fake news" stories taking over the web. Since her defeat, there's been a lot of talk about websites posting fabricated stories about Clinton and their impact on voters -- not to mention the wave of Wikileaks ... allegedly fueled by Russia.