Any way for some reason the first 2 forward gears make it move in reverse.
I had this happen on my Ariens.
The first thing to realize is that these are "speeds", not "gears", because you're not changing gears when you change speeds.
Imagine a horizontal metal disc that is rotating, and a vertical tire that rides on the disc. If you move the tire towards the outside of the disc, it will turn faster. If you move the tire towards the center of the disc, it will turn slower. If you move the tire across the center to the opposite side of the disc, it will reverse direction. That is how your "speeds" work.
What's happened to you, is in your first two "forward" speeds that tire is still on the wrong side of the center of the disc. Everything is shifted toward that side, so that the top speed, the tire isn't close enough to the edge of the disc.
There are a set of rods and pivots that link the speed selector handle to the fork that pushes that "tire" side to side. The one in the back under the handles is often made of two pieces that are taken apart to fold the handle down. If that's the case, is it assembled properly (forming a straight line), or not together right (coming together at an angle)? That was my issue, and the fix took much less than it took to read this, but explaining how it works isn't easy.
Anyway, check the linkage. If that's not it, the advice above about the fork is the only other possibility.
As for one vs two wheel drive. My machines have a pin that links the wheel hub to the axle. On the left wheel, the pin goes through both. On the right wheel, the axle sticks out an extra half inch, and you can remove the pin from the wheel and put it into just the axle. Doing this retains the wheel on the axle, but allows the right wheel to free spin.
Sounds like you may have this on the left wheel...
As for the wheels not turning when you hit snow. It could be a belt slipping, or the friction disc may be worn out (or not pressing hard enough).
