Video playback: loop and speed control?

My #3 son has been making short vids and putting them on youtube etc. teaching uke and guitar playing. I mentioned to him that years ago on Win98 systems I had a video player (shareware or freeware, I think) with really good controls on it, so you could tag a start and end point and loop inside a vid (I think it only did mpegs, but maybe a couple of the other old formats as well), and also control the playback speed, which is really great for using on things like this - you can pick the start/end of a certain riff, slow it waaay down, and see what's going on a whole lot better than you can at full speed.

I think this sort of thing would be very beneficial for his viewers (and his Pop, too!) to use with downloaded videos, but damned if I can find that old one (probably doesn't work on XP or Vista anyway) and the explosion of video-related software has created such a madhouse of choices that it would take days, if not weeks, to go through all of them...

So: can anyone give me some pointers to video playback software (hopefully free or at least inexpensive) that does let you select and loop with speed control?