Just last week got a home theatre system with Blu Ray. Seems discs take too long to play when going to another track and my screen turns green for a minute before resuming the picture.

Is this normal?

What's your idea of "too long to play"? Many Blu ray players do take longer compared to DVD, but that's mostly due to content of the disc you're loading. May help to know what kind of Blu ray player you have, and some possible searching on the threads.

All the software control that the studios could have been using over DVDs, to control whether you can skip trailers or other control issues, all of that was mostly ignored on DVDs. There is more possibility for control, and it is actually used on BDs. There is all sorts of annoyance on discs, just something to deal with. With earlier or lower-end players, the speed is probably not as good, also. I tend to fire up the bluray player and get the disc in ahead of time by a couple minutes, not after everyone is sitting down waiting for a movie.

I bought a Phillips home unit reduced to $198 at Walmart.

Model number? Based on the times I've been to Walmart their electronics (tvs, laptops, etc) tend to be on the low end (cheaper).

When did you buy it? If possible, I would return it and get a much better player for less money. Here are two excellent options for around $100:

Panasonic DMP-BD65
Sony BDP-S370

You can even jump up to one model up from those units and still stay under $200 and you'll be much better off. One of the realities of Blu-ray players is firmware updates and Panasonic and Sony are two of the best at keeping their players current.

I am not sure what you mean "between tracks". As already mentioned, blu ray players do boot up slower than DVD, but once the movie is playing there should be no difference.

As for the "green screen", that sounds like an HDMI synch problem. Check to make sure your cable is secure on both ends. You may need a new cable.