Golf driver goes 200 yards straight then 200 yards to the right? Why ?

I used to do the exact same thing. The most likely cause is that you're opening the club face at the point of impact, this causes side-spin on the ball. The ball appears to start straight but as wind resistance slows it down and the side-spin increases the sideways movement and it trails way right before it finally lands. Its kind of like a baseball pitcher putting side-spin on a pitch to throw a curveball, except in golf that side spin is bad.

I fixed my slice almost instantly with one simple tip from my golf buddy.

He showed me a better way to grip the club. I was just grabbing the club the way it felt natural - with my palms facing each other. He had me twist my left hand as far to the right as I could. So you start by grabbing the club with your left hand - with your palm toward your body and back of the hand facing directly away from you. This feels really awkward but it works. Then place your right hand on the club just the way it feels natural (but keep your left hand twisted).

What this does is it forces your left hand to twist as far as possible BEFORE you start your swing. Your hand can't move any farther in that direction, so you can't accidentally open up the club face as you swing. Anyway its worth a shot.

Also, I do strongly suggest getting fitted by a golf shop with a good launch monitor. When I bought my first driver I thought I'd need the softer shaft and steeper club face angle. I took it to the range and couldn't hit farther than 180 yards and every shot took a huge right turn. Most of my shots hit the side fence. I ended up returning that club and going to a small golf shop to get fitted on their monitor. Turned out I needed the stiffer shaft and the lower angle club face (the exact opposite of the club I tried originally). With the proper club I was driving it straight and hitting the back fence (225 yards) halfway up. On the course my drives go about 260-280 yards total (including roll).

that is the most common swing flaw that high handicap golfers make.   

that shot that curves to the right is called "slice".   the cause?  open clubface at impact and incorrect swing path.  

If you get custom fitting, you can see your swing flaw with a launch monitor and I suggest you find a qualified golf clubfitter and not just a salesperson at a golf shop.

The straight shots are striking the ball at the correct angle. The others are not.

The simplest answer is that the clubface is open at impact.

What causes it?  Without seeing your swing it could be any number of faults.  Make sure you're not tilting the clubface (the loft) and that the ball is positioned off your front foot.