Too much light is just as much a pain to work with as too little light!
Shot 1 ; good pose, but your problem is two fold. First you have a white horse which is very suseptable to being blown out (as has happened) and in the bright sunlight camera meters can get tricked into overexposing - so I nearly always set the camera to underexpose each shot by up to a full stop (either -1 on exposure compensation or underexposure in manual mode); that would help limit the chances of blowout on the white horse. Also the other problem is the angle of lighting - the light is behind your subjects so the faces of the horses and people is being shadowed - which is a big problem as those are the highdetail areas that you want clear in the shot - so turn them around so that the light is lighting the faces (not directly into the sun since then they will all be blinking) and position yourself so that your shooting with the light behind you - say get them to turn left or right then one side of their face would have sunlight on it.
Most of your other shots show good lighting position, but sadly blown highlights whenever the sun is free of the clouds. A big tip is to read up on using your camera histogram - its a very important feature of your camera and is the best way to get an idea if a shot has any overexposed or underexposed areas. Then you can always adjust your settings to compensate and shoot again.
By comarpison your shots taken when the sun was clouded over are showing far more detail and less overexposure (so you have to take note of the sun and when its blocked shift back to normal exposures else you will get very dark shots).
Overall I really like your eye for the shots and most of my gripes have been with techincal issuses and that is mostly the overexposure problem. Metalic bits are likley to always blow out in such lighting so don't worry about them too much, but do try to limit blowing out as much as you can.
Also with regard to vista go to your user account point (that little image in the start menu where you can set your account password and such. In that section look at the list of commands and at the bottom should be "Turn user account control on/off" click it and turn it off

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Finally I like the dog shots, but the second one really needs the rest of his jaw in teh shot I think - it looks rather cropped off as it stands. That or move in closer so that the eye areas are more dominating.