All of my footage is white!

Windows 10 64-bit

Premiere Pro 2015 CC

16gb RAM

Nvidia GeForce 8800 GTS (old card, but it's hardy and works well)

Everything is up to date.

I was in the middle of editing yesterday, and suddenly Premiere crashed (which seldom happens anymore). An error message flashed on the screen too quickly for me to see it. When I restarted Premiere, all of my footage was white. Also, Premiere changed the readout in the bin as 30.00fps, but the footage is 23.976 fps. When I check each file in Properties, it is correct.

I am using m2v and/or mpg.  I've been using some version of Premiere since 5.1 back in the day (oldster!), and I've never experienced this before. I've lost an entire day trying to figure this out. Here's what I've done to try to fix it.

Lots of reading. Lots of places, including here.

I read here about Mercury Engine Software in Rendering.  I thought to change or delete that, but it's greyed out, so I can't do anything with it.

I also read here that this is a "thing" and nobody knows how to fix it. I hope that has changed.

I've rolled my video drivers back.  Nothing changed.

I updated them back to where they are.  Nothing changed.

I uninstalled/reinstalled Premiere THREE TIMES.

The first time, nothing changed, and everything moved really slowly.  Also, when I pressed Play, nothing in the sequence played. (I dragged some audio & video down there just to see)

The second time, nothing changed. Still white.

The third time, I cleaned my registry and deleted my preferences, and when I opened Premiere for the first time and imported footage, it was fine.

Then I added a Loop button to my monitor screens, and everything turned white again.

I also imported various other formats, i.e., avi, mov, mp4, and even divx, which I know Premiere doesn't like. Interestingly, the mov will play, the mp4 will play, the avi's will variably play and not play, and I get a msg that the files are either unsupported (not true) or corrupted (not true). I don't get it---these are videos that I recently exported using available, workable codecs; they play just fine in all the standalone players I have, and they all played here before yesterday.

Can you help me?

Thank you.