PPC Problem I Can't Resolve

I have run into a problem with an Adwords account that I have never seen before. Maybe someone here can tell me it's normal.

I spent a great deal of time optimizing a campaign with tight ad groups and keywords in those ad groups. I worked with my ads until my CTR was consistently 2.50% and my conversion rate was consistently 10-13%. The product is a free download 30-day trial of software, fully-functioning.

Well, the problem is that I went from 10-13% conversions to zero conversions literally within the span of 48 hours. It has been five days with no conversions.

I have tested every piece of my landing page. I have a video on the page and asked several friends of my mine with different browser configurations, etc. to tell me if they have issues with the page loading, etc. Everything checks out as working fine. I went through the landing page and conversion process and everything worked fine. The only conversion I show is my own.

I would expect that some ads might stop performing over time, but not overnight like this. Has anyone seen anything like this before?