I'm no techy when it comes to computers, so here is a dumb way of how I add vids from these kind of sites to my PC.

This works for me using IE.

Let the video play in full in the website it comes from. Replay again just to make sure.

Click on Tools, then select Internet Options.

Under Browsing History select Settings.

Click in View Files. This will open a window showing all Temporary Internet Files. Click on size so the biggest files appear on the top. The file you are looking for will be there - just copy and paste to where you want to file it. Works every time.

Hope this helps. I was frustrated as hell to seeing hot vids that I couldn't keep until I figured out the above.