So, last week, right before I went off on vacation, I got a new laptop at work. My old one had it's video card go out and I'd had it for several years. Well, I got everything transferred over last week so I could hit the ground running after getting back from vacation.
Well, yesterday, I started noticing that it was taking a very long time to open pictures from the file explorer, so I changed to a different program (from the windows default) and it seemed to work fine after that. Later in the day, I noticed that other files were taking a long time as well, in fact, nearly every file I opened took a long time.
I did some research and read that there could be problems with network drives which could cause this problem, so I disabled all my network drivers, and the problem persisted. So, I searched the the registry looking for the \\ that would be at the front of a networked machine (either name or IP address) to see if anything in my Windows registry was pointed to a network device, and surprise surprise, I found that one of my software programs had it's executable pointed to my old laptop from when I had connected to it to remove old files to copy to the new one. So, I changed the path from the old machine to this one, and my files started opening up fast as expected.
So, if you have that problem, you may want to take a look at that.